If You Want To Get An Airkill, The Theory I've Found Is With The UAV. The Best Strategy To Use While Attempting This With The UAV Is To Be As Far Away From Your Target As Possible,  Then You Will Need To Begin Moving Forward While Decreasing Your Altitude Dramatically At The Same Time To Pick Up Enough Speed To Ensure Your UAV Will In Fact Kill The Enemy On Impact.

This Trophy Requires:

Roadkill An Enemy With Any Helicopter