This one is a little tricky, because you have to fly one chopper into another. The third area has you remotely controlling a helicopter. Take control of any of the boats, then slam it into the beach party. With that done, Angel will fly you to the next area.
If you can't do it with one pump, slam it into another, and another, until it explodes. After that, slam the vehicle into the indicated gas station pumps to blow it up. Note that the count only goes up when you kill a pedestrian, rather than merely wound them. You'll take control of it, and you just need to run over 15 people on the sidewalks. Hang out in the chopper until it gets to the destination, then shoot the RC gun at the indicated car. Remember that device Angel gave you forever ago that lets you remotely control cars? Now, it finally has a use.
