Near the end of the City Streets in the Prologue, the very first level, you will come to a right turn and in the distance you will see the monstrous Straga. As you approach him, red spikes will emerge from the ground, preventing you from going back from where you came.
Quickly pick up a car with the
to aim your reticle up and slightly in front of the oncoming helicopter and press
to throw the vehicle, if you hit the helicopter, you will knock it out of the sky and destroy it, achievement done, simple, but can be missed.
There is another opportunity to get this as the helicopter circles around and comes from where the red spikes blocked your path, but this is harder to hit.
If I've missed something or you have a criticism, let me know and I'll correct it.
Happy achievement hunting!