Table 8: System Operating Expenses (excluding Regional Jet Contract) per Aircraft,,,,,,,, Network Carriers,,,,,,,, Ranked by 2006 Performance,,,,,,,, (Cost in Millions of Dollars Excluding Regional Jet Contract Expenses per Aircraft) ,,,,,,,, 2006 Rank ,Network ,2001,2002,2003,2004,2005,2006,"Change 2001-2006" 1,Delta,21.974,21.367,23.624,30.132,32.130,35.880,13.960 2,United,31.130,28.311,24.236,28.167,30.677,33.461,2.331 3,Continental,22.071,20.920,20.762,22.899,26.154,28.461,6.390 4,American,25.247,23.281,22.867,24.647,26.462,28.045,2.798 5,Northwest,23.544,22.009,21.619,23.662,26.943,27.205,3.661 6,Alaska,17.627,18.666,18.944,20.875,21.840,24.994,7.367 7,US Airways,27.123,21.480,21.176,20.173,19.371,22.351,-4.772 ,7-Carrier Average,24.818,23.041,22.540,25.198,27.161,29.409,4.591 "Source: Bureau of Transportation Statistics, Form 41 Airline Financial Data",,,,,,,,