I'm interested to see how airlines will work to maintain their profit margins under pressure of rising fuel prices. On the roads, our answer is to produce more fuel-efficient cars that spend less energy to get from A to B. For an airline, there's a bit more of an investment in the vehicles they have, and they're expected to have a fairly long life, so on that basis alone they will be slower to change, but keep in mind that fuel efficiency in aircraft has been steadily improving for decades now. Optimising for efficiency always has limits, and we might be reaching those now. Pretty soon they'll just have to redesign from the ground up, like blended wing body planes.
Or they might have to change to something else entirely. However, for something to usurp planes as the default mode of transport for humans over long distances, it would need to be better not just on fuel consumption but comparable in raw speed. We won't accept something that takes a week where a plane takes just an hour, so if we're talking about trains, boats or blimps they'll have to be super-fast.
Mokalus of Borg
PS - Probably won't be blimps, then.
PPS - At least not for the rushed business traveller.