Jet aeroplanes are horribly inefficient, and waste colossal amounts of precious energy. And jet fuel is not even taxed...
There is a limit to how efficiently you can push large lumps of metal very fast through air. Jet planes will become more efficient in the next few decades, but not nearly enough to make them cheap in real terms. Likewise, other energy sources must come from somewhere -- electricity and hydrogen need power stations to make them.
Therefore when oil reaches its true price, jet planes will vanish, except for very expensive specialist uses such as the military.
If we can't break ourselves of the habit of international travel, we will have to go back to ships -- or turn to airships.
Airships use very many times less fuel, but are really not all that much slower than planes, especially as they do not need runways and airports. You could have an international flight landing near your town, and dropping you off right by your Majorcan villa -- no driving, no parking, no waiting. Probably quicker overall, and you could walk about inside the aircraft and not get thromboses in your legs. Oh, and they can run on biodiesel.
Some analysts are saying that just about now we have reached the peak volume of oil use -- from here the volume can only go down and the price can only go up.