S21 supersonic business jet
In the early 1990s, Gulfstream Aerospace and the Sukhoi Design Bureau began a joint effort to develop a supersonic small business jet, code named the S-21. Due to questionable market demand for commercial supersonic air travel, commitment to the project weakened and delays mounted. 
The S-21 would be capable of sustained cruise at Mach 2+ and much research and development has gone into the management of the troublesome transonic effects phenomena associated with near Mach 1 air speeds.
As in 2012, the project did not received any funding for the 2013-2025 development period and appears to be cancelled. 
Subsequently, Russian power plants were examined - the D-21 (AO "aircraft engine") and VK-21 (AMNTK Soyuz). In 1999 these passed bench tests. Extensive work was conducted on an improvement in their characteristics, a decrease in the level of the harmful emission of the exhaust gases, and also the decrease in the level of noise.
In November 2000 Sukhoi proposed to China to carry out a joint design of the supersonic administrative passenger aircraft of the second generation of class C-21.
The Sukhoi-Dassault supersonic aircraft Falcon will have a length of 31 m and a "duck" aerodynamic scheme. According to reports, the company Dassault as a possible power exploring alternative engine SNECMA M88 organization applied for fighter "Rafale", as well as F414 American company General Electric. The company intended to use the mixing jets instead of afterburner chambers to reduce noise; more details were expected in October 2003, at the Conference of the National Association of Service Aviation (NBAA) in Orlando (Florida pcs). For the evolving design of a maximum range of about 7500 km.