The Su-33 is a Russian fourth-generation carrier-based air superiority fighter developed for the Russian Navy. It officially entered service in the summer of 1998; by that time it had already been receiving improvements for nine years. Compared to the prototype, the Su-33 has larger folding wings, up-to-date navigation equipment, higher thrust to weight ratio, increased weapons load, and its air refuelable. Due to these unchallenged advantages the Su-33 became the most powerful ship-based fighter in the world. It's in service with the Russian 'Admiral Kuznetsov' heavy aviation cruiser.