A couple other factors coming into play:
Natural gas is becoming very plentiful via the technique of "fracking". Its effect on aviation is indirect, replacing liquid petroleum in terrestrial works like power generation and surface transport. Many city buses and delivery trucks are using natural gas already.
(I am scratching my head about the ultimate source of this very-deep gas source; it seems too deep to have come from rotting dinosaur carcasses. And a parallel question is - where did all the methane on the planetary giants in our solar system originate?)
Whatever its ultimate origin, natural gas use frees up diesel fuel and Jet fuel. And while Europe is not pursuing nuclear, it also frees up oil for aviation.
