Yeah, we have them down in Florida too, and I can personally attest to them. I've been busted by airplane twice. First time was the SR
524 at I-95 exit in Cocoa on a Labor Day. Second time was at the SR
44 at I-4 exit in Deland on the way to work.
Both times it was an aircraft (Cessna 172) circling one side of the overpass and 4 to 5 State Trooper cars lined up on the on ramp on the other side of the exit. The plane radios down a speed and description of the vehicle (green caravaan, inside lane e.g.) and as you cross the overpass, one of the troopers hops on the interstate behind you. The cop tells you that you have been clocked at such and such a speed by an aircraft.
I've watched them in action a few times other than that, and listened to them on the scanner at least once. Traveling the state for job I've seen them in Niceville (I-10 and SR 85), Tallahasse (I-10 near US 27), the Sarasota causeway on I-75 and the 528 and I-95 exit in Titusville.
Every time I've seen them its been a C 172, usually with State Trooper painted under the wings, one word one each side.
[Edited 2004-12-29 02:26:00]