Soviet Union
The Soviet Union
The USSR's principal combat aircraft was the Ilyushin Il-2, also known as the Sturmovik, or "Flying Tank". It earned this reputation because of its excelling qualities in air-to-ground combat, according to Encylopedia Britannica, it is "generally considered the finest ground-attack aircraft produced by any nation during World War II", (Britannica).
"The Il-2 was a single-engine, low-wing monoplane 38 feet (11.6 m) long and 48 feet (14.6 m) in wingspan," (Britannica).
When it first entered mass production, it had available "two 23-millimetre cannons and two 7.6-millimetre machine guns mounted in the wings". In addition, "the aircraft could also carry about 1,000 pounds (450 kg) of bombs", (Britannica). The Soviet Union later upgraded the cannons from 23 millimetres to 37 millimetres and outfitted it with a dense armor plating, that earned it its name as the "flying tank". It was an essential component of the Red Army's tactics and ultimate victory in the Eastern front.