Operating costs for US major airlines are primarily aircraft operating expense including jet fuel, aircraft maintenance, depreciation and aircrew for 44%, servicing expense for 29% (traffic 11%, passenger 11% and aircraft 7%), 14% for reservations and sales and 13% for overheads (administration 6% and advertising 2%). An average US major Boeing 757-200 flies stages 11.3 block hours per day and costs $2,550 per block hour: $923 of ownership, $590 of maintenance, $548 of fuel and $489 of crew; or $13.34 per 186 seats per block hour. For a Boeing 737-500, a low-cost carrier like Southwest have lower operating costs at $1,526 than a full service one like United at $2,974, and higher productivity with 399,746 ASM per day against 264,284, resulting in a unit cost of $cts/ASM against $cts/ASM.
