The P-63 was a vastly improved "version" of the P-39. Although they look quite similar, they are functionally completely different and no parts can be swapped into one another. The Kingcobra features a laminar flow wing, four-bladed propeller, and various other airframe changes. The Kingcobra saw massive use by the Soviet Union during World War 2. Although the P-63 was seen as a good aircraft in the US, it was ultimately rejected as it never passed the requirements set by the USAAF (United States Army Air Force). 3,303 Kingcobras were built and over 70% were sent to the Soviet Union by ferry pilots. The A-5 block was essentially an up-armoured XP-63A with provisions for more fuel. It also featured the 12 cylinder Allison V-1710-93 engine which could produce an impressive 1,500 hp at sea level. The Kingcobra, although played down by Soviet officials, was very successful in its use for air combat. It would also receive the NATO reporting name "Fred" after the war.

The P-63A-5 (USSR) is a premium Soviet fighter that has been in the game since the start of the Open Beta Test prior to Update 1.27. It is essentially the P-63A-5 found in the US tree but has better reward modifiers. The Kingcobra shares a few similarities with other Soviet fighters. It features a high calibre cannon, succeeds at low altitude, and is overall a manoeuvrable aircraft. However, unlike many of the fighters in the Yak line, the Kingcobra has a very high structural speed limit of almost 900 km/h (562 mph), which is incredibly fast for its battle rating. It does compress at high speeds, so players should be careful when performing aggressive dives at low-altitude. Overall, the P-63A-5 is a capable fighter thanks to its various improvements over the P-39.