Instructions
Basic Flying
Press the "Y" button to enter the helicopter alone or with accompanying Saints.
Press the "A" button to start the rotors and take off. Press the "A" button while in flight to ascend.
Press the "X" button to descend.
Push the left joystick forward to fly straight ahead and push it left and right to make the helicopter drift in that direction.
Press the "LB" and "RB" buttons to turn left and right respectively.
Combat
Train the on-screen reticule onto your target until you see a green box appear around the vehicle.
Keep the reticule trained on the target until the green box turns red. The red box indicates that you've locked onto your target.
Pull the left trigger to launch your rockets. Your shot destroys the vehicle in your sights unless it passes under a bridge or turns a corner around a building at the last moment. If that happens, your shot explodes harmlessly, but you still have that vehicle in your target lock.
Press the "Y" button while in flight to bail out of the helicopter. Press the "Y" button again while in free fall to open your parachute.