Alternately, this would be less of an issue if customers were willing to pay more to fly on an airplane, then airlines could make the amount of money with fewer passengers on the plane. As it is, there's fixed costs (crew, the plane, fuel to a certain extent) to flying an airplane somewhere regardless of how many people are on it, and the only way to make money is to charge enough to recover those fixed costs. You can either charge more per passenger or you can fit in more passengers. The cost for an additional few inches of legroom on United is about $40 on a larger plane, about $20 on a commuter plane. I understand that some people can't afford to upgrade, but then packing more passengers in benefits those people, presumably -- they'd rather have the lower fares than the extra legroom.
I'd love to pay 1.5x the cost of a normal airline ticket if airlines removed half the seats and gave more space, but there are several reasons that they don't/won't do that. First class tickets usually cost 2.5x-3.5x the cost of a coach-class seat, which is pretty hard to justify for any middle-class patron.
The massive costs required to enter the market prevent fresh competition and fresh models, and we really need to find a way to fix that.
