Join Date: Jan 2005
Location: New York, NY
Programs: UA, AA, DL, Hertz, Avis, National, Hyatt, Hilton, SPG, Marriott
Posts: 10,074
It was alphabetical, and US carriers mostly went first. 002 was BN, 005 was CO, 006 is DL, 007 was EA, 010 was NA, 012 was NW, 016 is UA, 026 was PA, etc.