To get a private jet, first get a Packer (found near the airport) and park it facing the airport fence. Next get a bike or run up the back of the Packer. If you are on a bike you should hit the fence and be thrown over it, if you are on foot you can jump up and climb over the fence. When you are in the airport grounds look around and you will find Dodo's, Helicopter's and a private jet. Get in the jet and fly away.
Remeber to turn a plane you have to use R2 an L2 aswell as the left analog stick.
If you fly alot you will get a pilot license and you can drive through the airport gate.
Added by: GTA Oct 30th 2004, ID#11353