This trick requires the ability to hijack helicopters and Jump Kick so that you 
can fly towards the helicopter. You can also use the Whipfist's Grab upgrade to 
latch onto an enemy helicopter. Double Jump can also be useful. To start, jump 
up, and Jump Kick or use the Whipfist Grab to latch onto the first helicopter. 
Do the button event to kill the pilot. Fly up as high as possible, and look for 
the next target. Make sure to use the Lock On ability. Jump out of the current 
helicopter, and Jump Kick towards the next helicopter. You can keep doing this 
as long as there are helicopters. If you fall, quickly use the Whipfist Grab. 
Note: This can be very challenging, but if done successfully you can attack 
numerous helicopters without ever touching the ground.