F-19 is the designation for a hypothetical US fighter aircraft that has never been officially acknowledged, and has engendered much speculation that it might refer to a type of aircraft whose existence is still classified.
Since the unification of the numbering system in 1962, U.S. fighters have been designated by consecutive numbers, beginning with the F-1 Fury. F-13 was never assigned to a fighter due to triskaidekaphobia, though the designation had previously been used for a reconnaissance version of the B-29. After the F/A-18 Hornet, the next announced aircraft was the YF-20 Tigershark. The USAF proposed the F-19 designation for the fighter, but Northrop requested the "F-20" instead. The USAF finally approved the F-20 designation in 1982. The truth behind this jump in numbers is Northrop pressed the designation "YF-20" as they wanted an even number, in order to stand out from the Soviet odd-numbered designations. Despite this, the designations YF-17 and YF-23 were not skipped (although YF-20, YF-17 and YF-23 all were prototypes and did not enter production phase).
The United States received the first Lockheed F-117 stealth fighter in 1982. During the decade many news articles discussed what they called the "F-19". The Testor Corporation produced a F-19 scale model. The company had decades of experience in producing highly detailed models that pilots and aerospace engineers purchased, and used its sources in the United States military and defense contractors. The CBS Evening News with Dan Rather and other media discussed the model after its January 1986 introduction; when the real stealth aircraft crashed in California in July 1986, news stories used the model to depict it. Representative Ron Wyden asked the chairman of Lockheed Corporation why an aircraft that Congressmen could not see was sold as model aircraft. The publicity helped to make the model the best-selling model aircraft of all time, but it did not really resemble the F-117, which no doubt pleased those working with the real, secret aircraft. The F-117 designation was publicly revealed with the actual aircraft in November 1988.