I love this game. My brother and I did a bunch of modifications to it (making the zip line longer, changing the properties of some of the vehicles, etc). PROTIP: go to that public airport, and steal a jumbo jet. Wait by one of the spawn points for the ones that take off and fly around. When one appears, follow it to the runway. Just as it's rounding the bend to get on the runway, hop on top and zipline your plane to the other one (being behind the other jet). Try and take off with it and have some tandem-jumbo-jet-fun