Although the project was very promising, but in connection with the collapse of the USSR and the difficult economic situation, the development of the Yak-43 was stopped in the early 1990s.
According to some sources, Yakovlev OKB continued to work on the Yak-43 and its development. Lockheed Martin was convinced of the possibilities of the Yakovlev Design Bureau in the field, because in June 1995, both firms signed a contract for the variant X-35.
Following the announcement by the CIS on September 1991 that it could no longer fund development of the Yak-41M, Yakovlev entered into discussions with several foreign partners who could help fund the program. Lockheed Corporation, which was in the process of developing the X-35 for the US Joint Strike Fighter program, stepped forward, and with their assistance 48-2 was displayed at the Farnborough Airshow in September 1992. Yakovlev announced that they had reached an agreement with Lockheed for funds of $385 to $400 million for three new prototypes and an additional static test aircraft to test improvements in design and avionics. The partnership began in late 1991, though it was not publicly revealed by Yakovlev until 6 September 1992, and was not revealed by Lockheed until June 1994.