In mid-1967 (yes, that's as specific as we can get), the North Vietnamese Air Force sent two An-2 planes to bomb a supposed radar station. These were light, propeller-driven planes, but it wasn't like they were trying to take out NORAD here. They had more than enough ordinance on board to blow up a tiny radar shack.
Unfortunately for the Vietnamese, they were wrong about the target. The building they saw below them wasn't a radar station, but an Air America station (Air America being the CIA-run transport service that operated during the war). The station was guarded by a single helicopter (on the ground), it's pilot, a mechanic and one crazy man with an AK-47.
Top speed: 0 mph. Maximum Altitude: Depends on throwing strength of the user.
The Vietnamese pilots flew in, firing their guns and ripping holes in the building. Then the crazy man with the AK-47 (he was reportedly a Thai mercenary) ran outside. Standing right in the path of the bullets and rockets pouring out of the two bombers, he raised his rifle and opened fire.
"Have at you, plane."
He emptied the magazine into one of the planes. And, to everyone's surprise except his, it went crashing to the ground. The other bomber, probably wondering what kind of new, deadly-yet-invisible anti-aircraft gun they were facing, decided to abandon the mission. The helicopter pilot and mechanic at the base, probably fighting the urge to just let that guy with the AK-47 take care of the fleeing plane, instead took off on their Huey helicopter and gave chase. Keep in mind, helicopters are not made for taking out fixed-wing planes. They're intended to haul troops around and maybe blow up some stuff on the ground. Improvising, the helicopter crew positioned themselves right above the enemy plane and used the wash from the propellers to push the Vietnamese aircraft downwards.
As if that wasn't badass enough, the mechanic on board the helicopter grabbed his gun and crawled down onto the rails of the chopper. Hanging on with one arm and shooting with the other, he sprayed a volley of bullets into the cockpit of the Vietnamese bomber, more than likely killing its pilot and sending the plane spiraling into the ground. His heroic actions were immortalized by this tasteful print.
Military Print Company
So at least one little kid got to live out his secret agent fantasies.
To date, it is the only air-air kill by the CIA, and is also the most awesome air-air kill ever. Even if, had they not intervened, the enemy plane would probably have gotten downed moments later by the crazy Thai mercenary and a well-thrown knife.
For more insane stories from the Armed Forces, check out 7 WTF Military Weapons You Won't Believe They Actually Built and The 10 Most Bizarre Military Experiments.