Alexei Tupolev, 75, an aircraft designer who led the design of the Soviet version of the supersonic airliner Concorde, died May 12. The Tupolev company, which announced his death, did not report the location or cause of his death.

The Kremlin said Russian President Vladimir Putin had sent his condolences to the family of the designer, the son of an equally famous father -- also an aircraft designer -- Andrei Tupolev.

Alexei Tupolev helped design mass-production passenger jets such as the Tupolev 134, still a workhorse of Russian and other former Soviet airline companies.

But one of his top projects was the creation of the Tu-144, a Soviet supersonic aircraft that so closely resembled the Concorde that it was nicknamed Concordsky.

It made its maiden flight Dec. 31, 1968, days before its Western rival, but remained excessively noisy and blatantly inefficient despite many modifications. Its flying range was also too small to justify the supersonic credentials. A crash at the Paris air show in 1973 effectively ended any international appeal the jet might have had.

A modified Tu-144 briefly operated between Moscow and the Central Asian city of Almaty, but it was quietly shelved after a second crash in 1977 killed three people.

The Tupolev company returned to the project in the 1990s and converted a Tu-144 into a flying laboratory. The company hopes to launch a Tu-244 in the next decade.

Mr. Tupolev redesigned the Tu-144 in the mid-1970s to provide the military with a long-range supersonic nuclear bomber. The swing-wing Tu-160, Blackjack by NATO classification, is still part of the Russian armed forces.

Mr. Tupolev also worked on the Buran space shuttle, which carried out one unmanned flight into space in 1988 but was later scrapped because of funding problems. The shuttle is now languishing in a huge hangar in the Baikonur space base in Kazakhstan, while an earthbound sister craft serves as an attraction in Moscow's Gorky amusement park.