The Tank Drop is a Russian support power available from the Palace, which, as its name suggests, paradrops three Rhino Tanks anywhere on the battlefield.
Note that the Industrial Plant does not reduce the Tank Drop's cost, as the tanks are delivered, not produced.
The AI will use Tank Drop at a clear space close to the center of the enemy base. If all enemies are defeated, the AI will target their own base, with the same circumstances. Additionally, the AI seems to prefer targeting Tank Drop in undefended areas of a base.
The Tank Drop is first usable in the campaign in Dragonstorm.