The Sukhoi Su-35S, the UAC's second military aircraft, is designed by the Sukhoi Design Bureau, a branch of the UAC. The aircraft is to serve as the interim for the Sukhoi PAK FA, Russia's first fifth-generation jet fighter. This is the second modernized version of the Su-27, where the first modernized version took place back on 28 June 1988, designated as the Sukhoi Su-27M, also known as the Su-35.
The Sukhoi Su-35S is a second military aircraft designed by the Sukhoi Design Bureau and intended to serve as an interim platform for Russia's first fifth-generation jet fighter, the Sukhoi PAK FA. This follows the initial modernization of the Su-27 on June 28, 1988, which resulted in the designation of the Sukhoi Su-27M or Su-35.