39 flights with unidentified reg, but as of March 8 2018, I've identified,
5x N6703D Boeing 757 Delta Air Lines B757-232
4x N670US 3x Boeing 747 Delta Air Lines B747-451 , 1x Boeing 747 Northwest Airlines B747-451
4x N803NW 2x Airbus 330 Northwest Airlines A330-323 , 2x Airbus 330 Delta Air Lines A330-323
4x N806NW 3x Airbus 330 Delta Air Lines A330-323 , 1x Airbus 330 Northwest Airlines A330-323
4x N810NW 3x Airbus 330 Delta Air Lines A330-323 , 1x Airbus 330 Northwest Airlines A330-323
4x N816NW Airbus 330 Delta Air Lines A330-323
3x N1602 Boeing 767 Delta Air Lines B767-332/ER
3x N172DN Boeing 767 Delta Air Lines B767-332/ER
3x N183DN Boeing 767 Delta Air Lines B767-332/ER
3x N332NB Airbus 319 Delta Air Lines A319-114
3x N346NB 2x Airbus 319 Delta Air Lines A319-114 , 1x Airbus 319 Northwest Airlines A319-114
3x N627DL Boeing 757 Delta Air Lines B757-232
3x N668US Boeing 747 Delta Air Lines B747-451
3x N6708D Boeing 757 Delta Air Lines B757-232
3x N762NC McDonnell Douglas DC-9 Delta Air Lines DC-9-51
3x N808NW 2x Airbus 330 Delta Air Lines A330-323 , 1x Airbus 330 Northwest Airlines A330-323
3x N813NW Airbus 330 Delta Air Lines A330-323
3x N817NW Airbus 330 Delta Air Lines A330-323
3x N820NW 2x Airbus 330 Delta Air Lines A330-323 , 1x Airbus 330 Northwest Airlines A330-323
3x N853NW Airbus 330 Delta Air Lines A330-223
3x N864DA Boeing 777 Delta Air Lines B777-232/ER
3x N866DA Boeing 777 Delta Air Lines B777-232/ER
3x N956DL McDonnell Douglas MD-80 Delta Air Lines MD-88
3x N960AT Boeing 717 Delta Air Lines B717-2BD
3x N973DL McDonnell Douglas MD-80 Delta Air Lines MD-88
2x N121DE Boeing 767 Delta Air Lines B767-332
2x N130DL Boeing 767 Delta Air Lines B767-332
2x N154DL Boeing 767 Delta Air Lines B767-3P6/ER
2x N172DZ Boeing 767 Delta Air Lines B767-332/ER
2x N173DZ Boeing 767 Delta Air Lines B767-332/ER
2x N176DN Boeing 767 Delta Air Lines B767-332/ER
2x N184DN Boeing 767 Delta Air Lines B767-332/ER
2x N186DN Boeing 767 Delta Air Lines B767-332/ER
2x N187GJ Bombardier CRJ Delta Connection (GoJet) CRJ-900
2x N197DN Boeing 767 Delta Air Lines B767-332/ER
2x N316NB Airbus 319 Delta Air Lines A319-114
2x N324US Airbus 320 Delta Air Lines A320-211
2x N335NB 1x Airbus 319 Delta Air Lines A319-114 , 1x Airbus 319 Northwest Airlines A319-114
2x N335NW Airbus 320 Northwest Airlines A320-212
2x N340NW Airbus 320 Delta Air Lines A320-212
2x N347NW 1x Airbus 320 Northwest Airlines A320-212 , 1x Airbus 320 Delta Air Lines A320-212
2x N353NW 1x Airbus 320 Northwest Airlines A320-212 , 1x Airbus 320 Delta Air Lines A320-212
2x N355NB Airbus 319 Delta Air Lines A319-114
2x N359NW 1x Airbus 320 Northwest Airlines A320-212 , 1x Airbus 320 Delta Air Lines A320-212
2x N364NW Airbus 320 Delta Air Lines A320-212
2x N3745B Boeing 737 Delta Air Lines B737-832
2x N3749D Boeing 737 Delta Air Lines B737-832
2x N386DA Boeing 737 Delta Air Lines B737-832
2x N399DA Boeing 737 Delta Air Lines B737-832
2x N515US Boeing 757 Northwest Airlines B757-251
2x N533US Boeing 757 Delta Air Lines B757-251
2x N552NW Boeing 757 Delta Air Lines B757-251
2x N555NW Boeing 757 Delta Air Lines B757-251
2x N591NW Boeing 757 Delta Air Lines B757-351
2x N593NW 1x Boeing 757 Northwest Airlines B757-351 , 1x Boeing 757 Delta Air Lines B757-351
2x N661US Boeing 747 Delta Air Lines B747-451
2x N669US Boeing 747 Delta Air Lines B747-451
2x N6704Z Boeing 757 Delta Air Lines B757-232
2x N6714Q Boeing 757 Delta Air Lines B757-232
2x N671US Boeing 747 Delta Air Lines B747-451
2x N672US Boeing 747 Delta Air Lines B747-451
2x N673US Boeing 747 Delta Air Lines B747-451
2x N674US Boeing 747 Delta Air Lines B747-451
2x N694DL Boeing 757 Delta Air Lines B757-232 'The Spirit of Freedom'
2x N697DL Boeing 757 Delta Air Lines B757-232
2x N707DN Boeing 777 Delta Air Lines B777-232/LR
2x N717TW Boeing 757 Delta Air Lines B757-231
2x N802NW Airbus 330 Delta Air Lines A330-323
2x N804DN Boeing 737 Delta Air Lines B737-932/ER
2x N805NW 1x Airbus 330 Northwest Airlines A330-323 , 1x Airbus 330 Delta Air Lines A330-323
2x N807NW Airbus 330 Delta Air Lines A330-323
2x N815NW Airbus 330 Delta Air Lines A330-323
2x N818NW Airbus 330 Delta Air Lines A330-323
2x N819NW Airbus 330 Delta Air Lines A330-323
2x N826AY Bombardier CRJ Delta Connection (Pinnacle) CRJ-200
2x N837MH Boeing 767 Delta Air Lines B767-432/ER
2x N838MH Boeing 767 Delta Air Lines B767-432/ER
2x N844MH Boeing 767 Delta Air Lines B767-432/ER
2x N855NW Airbus 330 Delta Air Lines A330-223
2x N857NW Airbus 330 Delta Air Lines A330-223
2x N858NW Airbus 330 Delta Air Lines A330-223
2x N860NW Airbus 330 Delta Air Lines A330-223
2x N861DN Boeing 737 Delta Air Lines B737-932/ER
2x N865DA Boeing 777 Delta Air Lines B777-232/ER
2x N912DL McDonnell Douglas MD-80 Delta Air Lines MD-88
2x N917XJ Bombardier CRJ Delta Connection (Endeavor) CRJ-900
2x N923AT Boeing 717 Delta Air Lines B717-2BD
2x N945DN McDonnell Douglas MD-90 Delta Air Lines MD-90
2x N972AT Boeing 717 Delta Air Lines B717-2BD
2x N992AT Boeing 717 Delta Air Lines B717-2BD
2x PH-BGB Boeing 737 KLM Royal Dutch Airlines B737-8K2 'Regenwulp'
2x PH-BGG Boeing 737 KLM Royal Dutch Airlines B737-7K2 'Koningseider'