Hey Ya'll,

I thought the thread on the use of wide bodies was interesting. So, that being said, what do you think the future of DL's narrow body fleet will be? The MD - 88/90 fleet and the Boeing version, the B717 fleet, ceased to be built in 2006. This means that they youngest of that fleet is 11 years. DL currently has multiple aircraft that (essentially) do the same thing: MD 88/90, B717, B737-700, and A 319 (I"m excluding the 737-8 and A320/321, as they have more pax it would seem).

DL is the largest operator of the MD-88/90/B717 fleet I believe. And I do enjoy flying them (esp the modified versions). But as the fleet ages - choices will need to be made. Any thoughts on what is going to happen? Will DL expand the 737 fleet? Of go with the A319 family?

One clear advantage would seem to be that with a reduction of types, the fleet would be simplified (as opposed to the current fleet, which does seem complicated).

Dave

A few things to consider:
- The replacement timeline varies significant for each fleet type, and even significantly within each fleet (e.g., A320s that have some much older and newer frames)
- The whole narrowbody fleet needs to be looked at in totality because the days of 1:1 replacement frames don't exist, they replace capacity and adjust frame size to network requirements. The overall strategy is to upgauge
- Even need to start considering the replacement strategy on the DCI side as well as additional CR2s, and older CR7 & CR9s start to approach the same age and cycles as many of the other fleet types mentions. Some of those are as old as some of the A319 & 717s.

What is known:
- The MD88 retirements start in 2017 and will be gone in the next 3-5 years
- The oldest A320s with the lower-rated engine retirements start in 2017
- Deliveries of 739ER, A321, and the C-Series

Speculated:
- No more orders for new-build A319CEO, A320CEO, 73G, 738s
- No more second-hand buys of MD90, 717, 757s as available frames are hard to find and the mod programs end
- Potential for a few opportunistic buys of used 738 or A320 (like the GOL) but these will be minor
- Additional new orders will got for NEOs/MAXs and next gen aircraft
- Additional C-Series to replace the bottom end of the fleet

PSU.DTW.SCE wrote:

A few things to consider:
- The replacement timeline varies significant for each fleet type, and even significantly within each fleet (e.g., A320s that have some much older and newer frames)
- The whole narrowbody fleet needs to be looked at in totality because the days of 1:1 replacement frames don't exist, they replace capacity and adjust frame size to network requirements. The overall strategy is to upgauge
- Even need to start considering the replacement strategy on the DCI side as well as additional CR2s, and older CR7 & CR9s start to approach the same age and cycles as many of the other fleet types mentions. Some of those are as old as some of the A319 & 717s.

What is known:
- The MD88 retirements start in 2017 and will be gone in the next 3-5 years
- The oldest A320s with the lower-rated engine retirements start in 2017
- Deliveries of 739ER, A321, and the C-Series

Speculated:
- No more orders for new-build A319CEO, A320CEO, 73G, 738s
- No more second-hand buys of MD90, 717, 757s as available frames are hard to find and the mod programs end
- Potential for a few opportunistic buys of used 738 or A320 (like the GOL) but these will be minor
- Additional new orders will got for NEOs/MAXs and next gen aircraft
- Additional C-Series to replace the bottom end of the fleet

GOL does not operate the A320, but they do operate the 737-700/800's. Sounds like to replace its MD-80's, I bet it's a 737MAX or the A320neo I think. Otherwise, more A321's and B739 could also replace some of its MD80 as soon as possible.

DL likes to get the most out of its airframes, so I wouldn't count on a huge NEO/MAX order just yet. I think a C300 or perhaps (if it ever sees the light) a CS500 order could be on the books to replace the 717 and older A320 and 737 frames. Most likely it'll be a mix and match depending on the routes they need the aircraft optimized for. Given Delta's size and history, fleet standardization is not high on their list of priorities.

- An A320neo / B737 Max order will come. DL will probably wait for the Max to enter service before making a decision to see what family meets their needs best. That said, the neo is looking stronger, in which case they might order both types (because of the political lobbying pressure).

- It'll be interesting to see if they will go for the A321LR or wait for the Boeing MoM to replace their 763s and 753s.

- More BBD orders to replace existing aircraft.

Of course I have no inside information, so I could be talking out of my backside here.

davescj wrote:

The MD - 88/90 fleet and the Boeing version, the B717 fleet, ceased to be built in 2006. This means that they youngest of that fleet is 11 years.

The 717-200 and MD-90 fleets were built a while ago, but DL just got them and they'll be in the fleet for quite some time (unless something drastic changes).

As DL has been refurbishing A319s and A320s, I'd assume all but the oldest A320s will be sticking around for quite a while as well.

davescj wrote:

One clear advantage would seem to be that with a reduction of types, the fleet would be simplified (as opposed to the current fleet, which does seem complicated).

Dave

From Delta's fleet page:

http://www.delta.com/content/www/en_US/ ... fleet.html

116 MD-88s with age of 26 years

69 A320s with an average age of 21.6 years, but some in there from 1990-91

65 MD-90s with age of 19.6 years

57 A319s with an average age nearing 15 years. 319s are a heavy shrink: economics will kill these before age and cycles.

91 717s with an average age of 15 years. Economics or parts availability will kill these prematurely. They won't fly to age 30 with Delta as 757s have.

If Delta really wanted fleet simplification it could replace, over ten years, 100% of those 398 frames with CS 100/300/500 aircraft. But it won't. Fleet simplification isn't demonstrated as a high priority with Delta's fleet acquisition moves over the last five years.

Even before ten years are up it will be time for the oldest 738s to go.

I really wish Delta decided to continue the super 89 mods to the MD-88. Not ready to see those birds leave! Just my opinion!

I think it's fascinating to fantasize about fleet renewals and defend our favorite aircraft families, but reality is DL will continuously renew its fleet in phases. It would be shocking if future orders weren't split between new build frames from Airbus, Boeing and Bombardier, as well as used late-model 737NG and 320.

Northwest1988 wrote:

I really wish Delta decided to continue the super 89 mods to the MD-88. Not ready to see those birds leave! Just my opinion!

Did they actually modify some? If so, how can you tell the difference between the original and the mod?

Given DL's thought process behind fleet utilization it seems unlikely to see a fleet standardization or simplification. Delta's use of aircraft typically is driven behind mission efficiency rather than fleet simplification. Delta also uses its size to leverage buying power over the manufacturers to get the kind of deals they are looking for. The past 7-10 years seems to show this as they tie some smaller aircraft to larger and/or take advantage of timing in the case of BBD and the CSeries. On the lower end of the narrowbodies it seems a foregone conclusion that the CSeries will lead the way to eventually (and when I say eventually I mean 8-10 years down the road) replace all 717's with C100 & C300's. The C500 at this time is a paper airplane so need to consider it. It has already been stated by others but they are correct in that a Max/Neo order is coming within the next 5-10 years to take up the remainder of the narrowbody fleet.

In my mind the real fleet question keeping DL executives up at night has to be what to replace the aging 757's with? 127 in the fleet used on a myriad of routes from ATL-MCO/LAS/SEA/BOS/SJU/MEX, RDU/PIT-CDG, SLC-HNL and so forth. This is the biggest problem area for DL in my opinion as it has no direct replacement as of yet. The A321 has yet to equal the 757's capacity and range and thus flexibility. The 752's in the fleet are now averaging close to 20 years in age and are utilized on all types of routes. I can only imagine that they have to be closely monitoring the A321LR as a replacement but that is still another couple of years away and if I recall correctly the A321LR does not have as high of an MTOW as the 752 but the range is supposedly slightly more and capacity is roughly the same I believe (correct me if I am mistaken).

That being said in 10 years I could imagine DL's narrowbody fleet looking like:
CS100 (75+)
CS300 (50+)
717 phasing out (to be replaced by C100/300)
738Max/A320neo (225+)
739Max/A321 & A321LR (225+)
752/3 phasing out

All this is dependant upon changing manufacturer dynamics also. I personally think that BBD will strike a deal with COMAC to support/co-manufacture the C919 as a larger expansion of the CSeries which would create an avenue for that frame into the West. Time will tell and should be fun to watch.

Probably a mixed fleet. And with oil predicted to stay low for the foreseeable future the 717/MD90s and 737NGs might still on for a long time.

PSU.DTW.SCE wrote:

A few things to consider:
- The replacement timeline varies significant for each fleet type, and even significantly within each fleet (e.g., A320s that have some much older and newer frames)
- The whole narrowbody fleet needs to be looked at in totality because the days of 1:1 replacement frames don't exist, they replace capacity and adjust frame size to network requirements. The overall strategy is to upgauge
- Even need to start considering the replacement strategy on the DCI side as well as additional CR2s, and older CR7 & CR9s start to approach the same age and cycles as many of the other fleet types mentions. Some of those are as old as some of the A319 & 717s.

What is known:
- The MD88 retirements start in 2017 and will be gone in the next 3-5 years
- The oldest A320s with the lower-rated engine retirements start in 2017
- Deliveries of 739ER, A321, and the C-Series

Speculated:
- No more orders for new-build A319CEO, A320CEO, 73G, 738s
- No more second-hand buys of MD90, 717, 757s as available frames are hard to find and the mod programs end
- Potential for a few opportunistic buys of used 738 or A320 (like the GOL) but these will be minor
- Additional new orders will got for NEOs/MAXs and next gen aircraft
- Additional C-Series to replace the bottom end of the fleet

Also to add to the what is known:
-DL is getting (4) 738s from GOL with Sky Interior, the oldest being about 4 years old. All are in storage, at MZJ I believe.
-DL does have an aging fleet and will be replacing a lot of frames in the 160-ish seat area being MD-88/90, old 320s and old 738s. We know the MD-88s are intended to leave within 5 years and probably 5 years from now DL will dwindle down on the -90 fleet. By that point I wouldn't be surprised to see some of the oldest 738s/320s go too.

So let's just get a theoretical look at what the narrowbody fleet will be like in 2022 (putting aside economical changes, aircraft accidents, etc.) Note: this is all my speculation.
57 A319s, 126 seats (no change from current)
48 A320s, 157 seats (21 retirements, all ships 3250 and older..3251 is 19 years old at the moment)
85 A321s, 192 seats (currently 13 a/c and adds the 69 on order)
91 717s, 100 seats (no change from current)
10 737-7s, 124 seats (no change from current)
77 737-8s, 160 seats (currently 73 a/c, adds the 4 GOL aircraft)
120 737-9s, 180 seats (currently 67 and adds the 53 a/c on order)
79 757-2s, 199 or 168 seats(currently 101 a/c NOT including the charter planes, 22 a/c retire from ships 623-684, all 75S remain)
16 757-3s, 234 seats (no change from current)
All MD-88s retired (would not be surprised to see ~10 still flying but the majority if not all will be gone
65 MD-90s, 160 seats (no change from current but retirement would begin soon thereafter)

DL has 75 CS100 aircraft on order which will be in the 110-seat range. I see them changing that to CS300 and if the CS500 ever comes to light to that as well. I don't want to speculate how that may or may not happen.

From what I broke down it is evident that an order in the 160ish area is needed as a lot of 320s will go along with -88s, and eventually -90s and 738s. I can see DL consolidating to the C-Series eventually to simplify the fleet, obviously excluding the 739 and 321.

TJerome postulates a theoretical look at what the DL narrow-body fleet will be like for the summer 2022 schedule.
"s-" equals supplemental and suspected comments
57 A319s, 126 seats (no change from current)
s- DL is considering adding another seat row to this sardine can, 132 seats
48 A320s, 157 seats (21 retirements, all ships 3250 and older..3251 is 19 years old at the moment)
s- DL is said to be opportunistically looking to buy used A320s.
85 A321s, 192 seats (currently 13 a/c and adds the 69 on order)
s- an 82 frame fleet is currently projected. Given the EB & DL appreciation for this offering and its fit, a-net and DL will see this as malleable
91 717s, 100 seats (no change from current)
s- DL will leverage the CS100 order in negotiations for remaining 717 frames. It will be interesting to see if Boeing scraps these frames at the 25 year D check / end-of-lease or sells them to DL. DL will likely have a 30 year preference for any frame it can economically acquire.
10 737-7s, 124 seats (no change from current)
s- agreed
77 737-8s, 160 seats (currently 73 a/c, adds the 4 GOL aircraft)
s- DL is said to be opportunistically looking to buy used B738s, suspect DL will see more GOL 738s, suspect this fleet will see 120 active frames
120 737-9s, 180 seats (currently 67 and adds the 53 a/c on order)
s- DL taking the full order, esp the last 20 frames would be disappointing. Is has been suggested that they have MAX upgrade options on this order.
79 757-2s, 199 or 168 seats(currently 101 a/c NOT including the charter planes, 22 a/c retire from ships 623-684, all 75S remain)
16 757-3s, 234 seats (no change from current)
All MD-88s retired (would not be surprised to see ~10 still flying but the majority if not all will be gone
s- this fleet will be fully retired
65 MD-90s, 160 seats (no change from current but retirement would begin soon thereafter)
s- given the the IAE engines on these frames, DL and a-net will heavily debate flying these frames x > 30 years.
75-125 CS*00 aircraft.
s- xx CS100; 1) a number of these craft are needed to address the R-jet issues. 2) this order gives DL flexibility and negotiating strength with the MD-95 fleet
s- xx CS300; will supplement MD-88 replacements.
s- xx CS300/500 will likely replace the A319s when they reach the 25year D-check
s- the 50 options are likely dependent on proposed versus actual reliably experience
****
suspect that DL would opportunistically like to acquire ~25 used NB frames a year, B738s & A320s. Recession and oversupply of ~12 year old frames may present "buyers" market opportunities starting in 2018

Really this is a stupid thread. As others have pointed out, DL already has or will be getting a boatload of small narrow bodies, some of which will be flying into the 2030's. A little soon to speculate beyond that isn't it?

I bet the 717 will be replaced by the DC-9s Delta is planning on bringing back as we speak.

I'm surprised by the comment that "economics" will kill the 717. It's a pretty-efficient little aircraft, particularly on shorter flights.

DFW789ER wrote:

Really this is a stupid thread. As others have pointed out, DL already has or will be getting a boatload of small narrow bodies, some of which will be flying into the 2030's. A little soon to speculate beyond that isn't it?

It's not stupid it all. The math says that DL has not ordered enough aircraft to only replace the aging fleet they have. There has to be another large order coming fairly soon, and that's where it's fun to speculate.

wjcandee wrote:

I'm surprised by the comment that "economics" will kill the 717. It's a pretty-efficient little aircraft, particularly on shorter flights.

It's overpowered with a small wing. You can get by with very short flights, but otherwise it's behind economically. Then you have the fact that it was a limited production aircraft, so parts and maintenance are going to be a growing issue down the road. And on top of that you have the low versatility with its low range and no cockpit commonality. I don't expect it to last beyond 25-30 years, which isn't too far away for the oldest examples.

MSPNWA wrote:

DFW789ER wrote:

Really this is a stupid thread. As others have pointed out, DL already has or will be getting a boatload of small narrow bodies, some of which will be flying into the 2030's. A little soon to speculate beyond that isn't it?

It's not stupid it all. The math says that DL has not ordered enough aircraft to only replace the aging fleet they have. There has to be another large order coming fairly soon, and that's where it's fun to speculate.

wjcandee wrote:

I'm surprised by the comment that "economics" will kill the 717. It's a pretty-efficient little aircraft, particularly on shorter flights.

It's overpowered with a small wing. You can get by with very short flights, but otherwise it's behind economically. Then you have the fact that it was a limited production aircraft, so parts and maintenance are going to be a growing issue down the road. And on top of that you have the low versatility with its low range and no cockpit commonality. I don't expect it to last beyond 25-30 years, which isn't too far away for the oldest examples.

They have already said the 717's will be used into the next decade. 20 years for the C-series, maybe more. They need to get rid of the old 319/320's but they are still covered.

Really all I can imagine is some CS300s or some CS500s if they come out.

DFW789ER wrote:

They have already said the 717's will be used into the next decade.

The next decade is less than three years and six weeks away. Yes, Delta 717s will still be flying on 1/1/2020. Thirteen or fourteen years from now, into the 2030s? I'll take the under on that. E2s and CS100s are going to make the 717s look very limited and inefficient.

MIflyer12 wrote:

DFW789ER wrote:

They have already said the 717's will be used into the next decade.

The next decade is less than three years and six weeks away. Yes, Delta 717s will still be flying on 1/1/2020. Thirteen or fourteen years from now, into the 2030s? I'll take the under on that. E2s and CS100s are going to make the 717s look very limited and inefficient.

Depends on the price of fuel. Delta is widely panned for getting as many years as they can out of their fleet, and I didn't say the 717's would make it to 2030. However, it's not inconceivable there are 717's around in 13 more years.

DFW789ER wrote:

MIflyer12 wrote:

DFW789ER wrote:

They have already said the 717's will be used into the next decade.

The next decade is less than three years and six weeks away. Yes, Delta 717s will still be flying on 1/1/2020. Thirteen or fourteen years from now, into the 2030s? I'll take the under on that. E2s and CS100s are going to make the 717s look very limited and inefficient.

Depends on the price of fuel. Delta is widely panned for getting as many years as they can out of their fleet, and I didn't say the 717's would make it to 2030. However, it's not inconceivable there are 717's around in 13 more years.

Not "panned" by analysts looking at their profitability numbers...

With 120 739's, 82 321's, and 75 C series, I would think Delta has plenty to replace the MD88's and the older 757's and 320's. I could see no more big orders for 5 to 8 years.

ehaase wrote:

With 120 739's, 82 321's, and 75 C series, I would think Delta has plenty to replace the MD88's and the older 757's and 320's. I could see no more big orders for 5 to 8 years.

It's still not enough. I'll go through some generalized math. Assume no used deliveries, just replacing what they have now, and that arriving and departing aircraft have approximately the same number of seats.

DL has about 122 739s and A321s left to arrive until 2019, and then there's the 75 confirmed CSeries that are over a year away from beginning to arrive. Delta has two older groups of domestic aircraft. Those that were delivered between 1987 and 1993 (peaking in 1991/92), and another group from 1995 to 2005 (building to a peak in '01). That first group consists of about 184 airplanes. The second includes over 300. The total is about right at 500. If Delta averages 30 years of service life for its current fleet, higher than what they have been getting, the 197 currently ordered will take care of retirements through 2023, which is coincidentally about when the orders end. But if they only get 28 years on average, a more accurate number that's maybe a little high yet, that means they need those 197 airplanes by 2021. So they're already tight with the current orders. But the larger problem down the road is the group from '95 to '05. Let's say a good-sized order (50-75) takes just five years from the order being placed to the last delivery. If they average the 28 years again, they need another order around 2019, and four more orders about every two years after that. Talk about a CapEx hit. Ouch. And this doesn't not take into account growing the fleet with new aircraft (could do that with used, but that isn't free either and creates more replacement liabilities sooner), nor does it account for something more important--fleet modernization. That's what they need for just replacing what they have. Delta has a created massive bubble, and they haven't ordered enough yet to fly over it.

97% of DL's 717 fleet is leased. (Don't they lease them from WN?) That to me signifies that they could park them pretty fast whenever the economics don't pencil out anymore. DL seems to place fleet orders gradually from all three major manufacturers, so I would expect that to continue.

deltadawg wrote:

Given DL's thought process behind fleet utilization it seems unlikely to see a fleet standardization or simplification. Delta's use of aircraft typically is driven behind mission efficiency rather than fleet simplification. Delta also uses its size to leverage buying power over the manufacturers to get the kind of deals they are looking for. The past 7-10 years seems to show this as they tie some smaller aircraft to larger and/or take advantage of timing in the case of BBD and the CSeries. On the lower end of the narrowbodies it seems a foregone conclusion that the CSeries will lead the way to eventually (and when I say eventually I mean 8-10 years down the road) replace all 717's with C100 & C300's. The C500 at this time is a paper airplane so need to consider it. It has already been stated by others but they are correct in that a Max/Neo order is coming within the next 5-10 years to take up the remainder of the narrowbody fleet.

In my mind the real fleet question keeping DL executives up at night has to be what to replace the aging 757's with? 127 in the fleet used on a myriad of routes from ATL-MCO/LAS/SEA/BOS/SJU/MEX, RDU/PIT-CDG, SLC-HNL and so forth. This is the biggest problem area for DL in my opinion as it has no direct replacement as of yet. The A321 has yet to equal the 757's capacity and range and thus flexibility. The 752's in the fleet are now averaging close to 20 years in age and are utilized on all types of routes. I can only imagine that they have to be closely monitoring the A321LR as a replacement but that is still another couple of years away and if I recall correctly the A321LR does not have as high of an MTOW as the 752 but the range is supposedly slightly more and capacity is roughly the same I believe (correct me if I am mistaken).

That being said in 10 years I could imagine DL's narrowbody fleet looking like:
CS100 (75+)
CS300 (50+)
717 phasing out (to be replaced by C100/300)
738Max/A320neo (225+)
739Max/A321 & A321LR (225+)
752/3 phasing out

All this is dependant upon changing manufacturer dynamics also. I personally think that BBD will strike a deal with COMAC to support/co-manufacture the C919 as a larger expansion of the CSeries which would create an avenue for that frame into the West. Time will tell and should be fun to watch.

I agree with your analysis. DL will buy on opportunity. C-series (CS-500 will get to bid once offered), MAX, or NEO.

But DL will buy opportunistically. If 717s are cheap enough, or used 738s... Or A320s. They use some aircraft intensely, some not.


Lightsaber

DL isn't afraid to buy used 717's, 737's, and Airbuses, if there is an opportunity, DL will reach out to it. The 753 has been a very reliable aircraft in the fleet, and I could see a long lifespan on these planes. In terms of new narrow-body aircraft orders, I don't expect it, only the addition of newer used aircraft that fit their fleet plans.

320 will go to 157 seats and get AVOD.
717 is already 110 seats.
MD90 is going to 158 seats; no AVOD

MSPNWA wrote:

DL has about 122 739s and A321s left to arrive until 2019, and then there's the 75 confirmed CSeries that are over a year away from beginning to arrive. Delta has two older groups of domestic aircraft. Those that were delivered between 1987 and 1993 (peaking in 1991/92), and another group from 1995 to 2005 (building to a peak in '01). That first group consists of about 184 airplanes. The second includes over 300..

Thank you. Is there a breakdown by type of the 184 acquired between 1987 and 1993 and the over 300 from 1995 to 2005? I would imagine both groups also include wide body aircraft, with lots of 767-300ER, 767-400ER, and 777-200ER, with 25 330-900 and hopefully 18 787-8 replacing the 767-300ER. .

Well, I see a sizable number of A319/320s coming available when and if AS/VX ever complete their merger.

http://finance.yahoo.com/news/delta-pil ... 20598.html

MONTREAL, Nov 25 (Reuters) - Delta Air Lines Inc pilots are expected to keep existing rules in their new labor contract that prevent the U.S. No. 2 carrier from flying aircraft above a certain weight on regional routes, in a blow to Embraer SA and Mitsubishi Heavy Industries Ltd , whose latest models exceed that limit.

The pilots' new labor contract will keep what is known as a "scope clause," which restricts planes heavier than 86,000 pounds and with more than 76 seats from being flown on regional routes, two sources familiar with the matter told Reuters.

Voting results on the new contract are expected on Dec. 1.

The clause effectively protects well-paid pilot jobs at major airlines, as it prevents the carrier from using bigger planes on outsourced regional routes, which generally pay less well and have inferior working conditions.

When planemakers such as Brazil's Embraer and Japan's Mitsubishi designed their latest regional jets, with heavier but more fuel-efficient engines, they expected the scope clause to have loosened, but unions have managed to hold on to it.

737 MAX maybe, A321neo, but almost certainly the CS300.

If/When the CS500 is launched, perhaps DL with be a launch customer?

ehaase wrote:

Thank you. Is there a breakdown by type of the 184 acquired between 1987 and 1993 and the over 300 from 1995 to 2005? I would imagine both groups also include wide body aircraft, with lots of 767-300ER, 767-400ER, and 777-200ER, with 25 330-900 and hopefully 18 787-8 replacing the 767-300ER. .

I just realized I made a mistake. I forgot to include the 717s. It wouldn't effect the first group of 184, but it will the second. We can add 91 more to the approximately 311 in the second group and extend it into 2006, so that's actually over 400.

Those two numbers include only narrowbodies except for the 6 remaining domestic 763s. So it's just what you would expect to be replaced with a narrowbody. I haven't looked at the widebody fleet yet.

MIflyer12 wrote:

davescj wrote:

One clear advantage would seem to be that with a reduction of types, the fleet would be simplified (as opposed to the current fleet, which does seem complicated).

Dave

From Delta's fleet page:

http://www.delta.com/content/www/en_US/ ... fleet.html

116 MD-88s with age of 26 years

69 A320s with an average age of 21.6 years, but some in there from 1990-91

65 MD-90s with age of 19.6 years

57 A319s with an average age nearing 15 years. 319s are a heavy shrink: economics will kill these before age and cycles.

91 717s with an average age of 15 years. Economics or parts availability will kill these prematurely. They won't fly to age 30 with Delta as 757s have.

If Delta really wanted fleet simplification it could replace, over ten years, 100% of those 398 frames with CS 100/300/500 aircraft. But it won't. Fleet simplification isn't demonstrated as a high priority with Delta's fleet acquisition moves over the last five years.

Even before ten years are up it will be time for the oldest 738s to go.

I don't understand why the airline would not want to profit from simplifying logistics by going for C-Series to replace all the mad dogs and 717's (and the A319's if the CS500 goes ahead and is the best suited replacement).