I'm having trouble understanding how air travel works.
Also all airports are considered adjacent to each other, because you can travel from one to the other by plane. However, a plane may not be used in two consecutive turns. When a player moves to an airport by road, the next player may travel by plane to another airport. The party disembarks at the destination airport and the next player must travel by road again.
I'm assuming that airports are adjacent only if you fly there from another airport. Is that right?