The stealth technology of aircraft is mainly reflected in the control of target signals such as radar and infrared. Aircraft using radar stealth are easy to identify from their appearance. This type of aircraft mainly reduces the radar reflection cross section by optimizing the appearance design. For example, the American F-117A, the entire aircraft is almost composed of straight lines and planes, which concentrates the radar reflection waves. Several narrow beams in the horizontal plane prevent enemy radar from getting enough continuous echo signals to determine whether it is a real target. Coupled with the special stealth design of the engine air intake, tail nozzle, canopy seams, landing gear and other parts, it makes it appear on the radar screen. L shows a smaller signal than a bird would show on a radar screen. In addition, American F-22, B-2, "Comanche" and other aircraft have adopted "plastic surgery". The radar reflection cross section is extremely small.