Stealth airplane use stealth technology  to avoid detection by features to interfere with radar, as well as to reduce visibility in the infrared, visual, audio, and radio frequency (RF) spectrum. Development of stealth technology likely began in Germany during World War II. Well-known modern examples of stealth airplane include the United States' F-117 Nighthawk (1981–2008), the B-2 Spirit, the F-22 Raptor, and the F-35 Lightning II.

Nighthawk  F-117

While no aircraft is totally invisible to radar, stealth airplane or aircraft make it difficult for conventional radar to detect or track the aircraft effectively, increasing the odds of a successful attack. Stealth is the combination of passive low observable (LO) features and active emitters such as Low Probability of Intercept Radars, radios and laser designators. These are usually combined with active defenses such as chaff, flares, and ECM. It is accomplished by using a complex design philosophy to reduce the ability of an opponent's sensors to detect, track, or attack the stealth airplane. This philosophy also takes into account the heat, sound, and other emissions of the aircraft as these can also be used to locate it.

Full-size stealth combat airplane demonstrators have been flown by the United States (in 1977), Russia (in 2010) and China (in 2011), while the US military has adopted three stealth designs, and is preparing to adopt the Lockheed Martin F-35 Lightning II.

Most recent fighter designs will claim to have some sort of stealth, low observable, reduced RCS or radar jamming capability, but there has been no air to air combat experience against stealth airplane.

F-117 Nighthawk