In 1975 Stankevicius became a test-pilot. He has accomplished spin testing of MiG-29. He flew 57 types of aircraft and had over 4000 hours of flying experience. In 1982 he was graded as a 1st class test-pilot.
In 1979 he was assigned to prepare for 11F35 („Buran“, USSR Space Shuttle).
In 1982 he became the first Lithuanian austronaut by passing all the required exams in February.
After September 1984 he trained to fly the space shuttle Buran. Stankevičius accomplished 14 test-flights with Buran's counterpart BTS-02 aircraft and 6 taxi tests with Buran. He was both the pilot and the commander of the space shuttle.
In 1990 Rimantas Stankevičius participated the Everett Air Show with a Su-27 fighter jet. Soon after his return home, he went to Italy to replace another USSR pilot in Salgareda Air Show. On September 9th, during a flight in the show in a Su-27 he started a loop in a lower altitude than he estimated and made an unintentional touchdown. He had an option to eject from the aircraft, leaving the plane to crash into the crowd, yet he chose not to and died in the crash, saving lives of hundreds of peoples at the show. Stankevičius is buried in Kaunas, Lithuania.