A few problems

Maybe I am not figuring this out correctly, but once I get to the stage where you need those helicoptors to blow up the building in construction, the helicoptors will only go up, down and side to side, but will not go forward. It will not go forward or backward. I am using the ASWD for direction (A for up, S for down, A to left and D to right). Are there any other buttons to use when I want the helicoptors to go FORWARD (not only able to move forward by using it side to side)? It is very frustrating!!

DJAusty about Grand Theft Auto: Vice City