Mafia Cheats

On the first mission in the airport (the one with Frank), you can get a car into the main area of the airport.
First of all, take one of the new, rounded cars to the airport as the car you select for this mission. You should get the Schubert Extra-6 at the beginning of this mission anyway, and that works perfectly.
It is important to only do this trick AFTER you have taken out the guys inside of the main building and Frank has run for cover. The car you brought will be parked in the last parking space on your right as you enter the airport for the first time. Make note of it but don't use it until after you've taken care of the guys inside.
On the cement posts opposite the ones that are on the right side of the main building in the airport parking lot (they'll be facing a field), there is a considerable gap between the leftmost post and the building it's next to. It looks wide enough for a car to squeeze through, and it is, but not without a bit of force. It's technically a little too small, but like most physics engines, the one in this game will allow you to force some solid surfaces slightly through each other.

Drive your rounded car as far into the gap as it will allow you (a bit of the front wheel should be visible past the post). Now, grab the older car conveniently parked next to the posts and position it directly behind your rounded car. Back it up as far as you can go without hititng anything, then floor it and ram your rounded car as hard as you can. Do this two or three more times and the rounded car should be far enough past the barrier to be driven out into the small passage behind the posts. Simply turn left from here and drive between the two hangars, run over the trenchcoat guards at full speed to kill them, and find your way to Frank in the back behind the other buildings. Take care to only make roadkill of his guard, and not him as well.

If your car kicks the bucket and won't accelerate significantly (hopefully you haven't been foolish enough to let it blow up), there should be a green Schubert Extra-6 parked back in the parking lot that you can open. Apply the same trick and resume turning your enemies into pavement pizza.