No Fly Zone,
Absolutely right. An excerpt from
https://en.wikipedia.org/wiki/Stealth_technology
".....During the 1970s the U.S. Department of Defense launched project
Lockheed Have Blue, with the aim of developing a stealth fighter. There was fierce bidding between Lockheed and
Northrop to secure the multibillion-dollar contract. Lockheed incorporated into its bid a text written by the
Soviet/
Russian physicist
Pyotr Ufimtsev from 1962, titled
Method of Edge Waves in the Physical Theory of Diffraction, Soviet Radio, Moscow, 1962. In 1971 this book was translated into English with the same title by U.S. Air Force, Foreign Technology Division.
[16] The theory played a critical role in the design of American stealth-aircraft F-117 and B-2.
[17][18][19] Equations outlined in the paper quantified how a plane's shape would affect its detectability by radar, its
radar cross-section (RCS).
[20] This was applied by Lockheed in computer simulation to design a novel shape they called the "Hopeless Diamond", a wordplay on the
Hope Diamond, securing contractual rights to produce the
F-117 Nighthawk starting in 1975.....".
......
More on that person could be read here:
https://en.wikipedia.org/wiki/Petr_Ufimtsev