Given how devastatingly effective both newly-invented tank and airplane technologies proved during World War I, it was only a matter of time before enterprising military designers on both sides of the Atlantic thought to combine them into a flying machine of armoured mayhem. And they almost succeeded. Well, at least the Soviets did.
In the 1930s, both the Americans and the Soviets realised the tactical advantages of being able to drop an armoured division behind enemy lines where it could wreak havoc on the enemy's soft spots like supply lines and command posts.
In America, tank developer Walter Christie designed a self propelled flying tank that employed a pair of biplane wings and rudder with a propeller driven by the tank's engine. In this scheme, the tank commander would also pilot the vehicle. "The flying tank is a machine to end war," Christie told Modern Mechanics magazine in 1932. "Knowledge of its existence and possession will be a greater guarantee of peace than all the treaties that human ingenuity can concoct. A flock of flying tanks set loose upon an enemy and any war is brought to an abrupt finish." If only.
Russia's initial attempts weren't any better. When Soviet high-command began looking into delivering armoured support to ground troops from the air, they took the most logical step and just dropped the tanks out of airplanes. No parachutes, just let them drop—woe to the guy standing in its landing zone. When that idea didn't pan out, they tried fitting parachutes to the tanks but that didn't work much better. They also experimented with strapping small tanks like the T-27 and T-37 to the bottoms of TB-3 bombers but the process proved treacherous and unwieldy. And given the relative value of a TB-3 bomber versus the lightly armoured tank it was carrying, the risk of having both shot down outweighed any amount of damage that the tank would inflict.
In 1940, famed Soviet aircraft designer Oleg Antonov struck upon the idea of converting the 29-tonne T-34 tank into a glider, tow it behind a pair of ANT-20 planes, and simply coast the armoured vehicle into enemy territory.
Dubbed the "Kryl'ya Tanka" (literally, "winged tank") and designated the A-40 KT, this prototype vehicle combined glider wings and a T-60 tank. The pilots manoeuvred the tankcraft by raising, lowering, and rotating the turret, which was connected to the rudder and ailerons.
It actually flew, once, in 1942. The T-60 was stripped of all non-essential parts to reduce its weight as much as possible, then attached to the glider wings, and hooked onto the back of a TB-3 Bomber. While the tank did get airborne, its massive weight caused the bomber's engines to quickly overheat, forcing the TB-3 pilot to cut the A-40 KT loose. Amazingly, the A-40 KT glided in for a successful landing whereupon the A-40 KT's pilot detached the wings and drove the tank back to the airfield. Unfortunately, subsequent experiments with the larger T-34 tank—which is what the Soviets really wanted to use—proved too heavy to work and the project was eventually shut down.
It wasn't until the US military later invented low-level extraction drop methods—whereby a C-17 swoops low to the ground, opens its rear hatch and drogue parachutes attached to the tank are deployed, pulling it out the door—that tanks began falling from the sky. We're still waiting, however, for those flying ambulances the 1920s promised us. Oh wait, there they are. [Kaiserslautern American - Anigrad - TIFO - Wiki]