Low-bid

Okay, follow me here: I fly from DC to Seattle once or twice a year. A modern airliner takes 3.5 liters of fuel per 100 passenger-kilometers. The planes are full (200-250 passengers). The trip is 4500 km long. Ignoring many things, including the jet stream, my share of the fuel works out to ~135 liters each way. A quick Google suggests jet fuel currently runs $1.65/gallon, which implies a fuel cost, round trip, of ~$120. A round-trip ticket (one stop) can usually be found for less than $300, and I've seen $250. And so as I sit in my bargain basement seat, I've occasionally wondered about maintenance.

Chinese Aircraft Maintenance.
Malaysia Airlines 777 on takeoff.