The whole point of taking a plane is to get somewhere else. Going to the airport lot, to load up the airplane lot, only to wind up back home at the end of it would be completely pointless.
And when people are upset about needing loading screens to go anywhere off lot in this game, I really don't know how fun they'd be with mandatory minigames before being able to get to whatever other lots. And while you could get around that by making the airport minigame skippable, it tells you a lot about a pack when its main theme is something you expect most people to wind up skipping.