I work in VFX and here is my input:

It is definitely a real Quadcopter at least some of the time. When the exhaust from the rotors interact with the environment, especially dust and smoke, that is when it is real. Moments like the final take off and after shooting at the dummies, that is real. He is not flying it. The final scene when he shoots out the rear car window, that's not how the window would bust out that is from a charge in the car. Also there is NO WAY anyone would let him blow this thing up. A real charge in the car would not have fire like that, so that is a Hollywood charge. I doubt the gun on the copter is really shooting.