The Great Patriotic War. Sasha Samokhin is a pilot fighting in the forward area battle who works out a «dog-fight formula», and Olya, his bride, works at an aircraft factory and helps Kazakov, the designer, to draft models of «Molnia» supersonic aircraft. Nobody supports these know-how, however soon the pilots realize that Sasha is right, and Kazakov gets an authorization from Moscow for construction of the new aircraft. After the victory over Hitler Germany the «Molnia» aircraft makes a round-the-world flight at supersonic speed. Source : www.mosfilm.ru