There is no specific cheat code for obtaining a helicopter on Grand Theft Auto: Vice City. However there is a number of ways in which you can obtain some of the better helicopters that are available to use in the game.
To get the police helicopter, one of the best helicopters in the game, you must first kill Diaz and get his mansion. When you enter the mansion got to the left and go through all the turns until you get to the top of the mansion.
At the top of the mansion will be an ordinary helicopter. Fly the helicopter to the downtown area and look for the police headquarters. On the top of the headquarters will be the helicopter. The hunter helicopter can be obtained once you have completed the ‘Cop Land’ mission.
Go to the police station in vice point and head for the locker room. Get the cop outfit near the showers. Walk out and get in the police car at the back and drive over to the Fort Baxter air base. Head into the base, climb up the first tower and jump off the side to get to the other side of the fence.
Go over to building where there is a stairway, walk across it and then get off near where the fencing stops. Now run over the other side of the base where the fencing stops and walk over to the opposite side. There, a hunter helicopter should be right in front of you. An easier way to obtain the hunter helicopter is to use the ‘pedestrians’ riot’ cheat.
The code is: Down, Left, Up, Left, X, R2, R1, L2, L1.
You can walk right in regardless of what you’re wearing as the soldiers will be shooting at each other.