> Since, as you might imagine, the planes themselves are an airline's biggest expenditure...<p>Is that true?<p>I'd have expected that, over the course of the life of a plane, the costs to fuel, maintain, or pay the humans associated with it's flights would be bigger than the initial purchase cost.<p>Edit: ChatGPT thinks fuel is the biggest expense at 2-3x the original purchase price over the life of the aircraft.