This game is casual in nature, meaning it's easy to get into, but Airport Mania quickly gets very challenging. I've always enjoyed multitasking and Airport Mania is a clinic on keeping track of multiple things at the same time. I think at a minimum you'll find it difficult to get the "Supreme Score" on the last level of this flash game.
Additionally the game was made to make people smile. It's meant to be a game to take players away from the grittiness of life and enjoy succeeding in the moment.
I hope you enjoy it!
(note: this has a fix to a version put up earlier that didn't work on NG ... but did everywhere else, apologies if you tried that one!)