Market Cap in Billions as of March 1, 2002

United - UAL - 0.745
American AMR - 4.21
Delta - DAL - 4.46
Continental - CAL - 2.08
America West - AWA - 0.131
Northwest - NWAC - 1.45
US Airways - U - 0.368
Alaska Air - ALK - 0.852
Southwest - LUV - $15.95

I'm no financial analyst, but I'll go out on a limb and say that if Southwest is the only airline in this group making money AND has a market cap larger than the other 8 "majors" conbined - they are a major airline.