In the F.U.B.A.R. challenge mode, Apache Helicopters will occasionally show up to try to wreck your day. They will fly in front and above your vehicle, following your direction with a slight delay. They use the same weapons as support choppers. However, they will wait for orders to fire their rockets.
TRhey have a large amount of health, but can be taken out with your gun fire and rather quickly with rockets and by making it fly 3 times into highway signs.