The Boeing Skyfox is an American twin-engined jet trainer aircraft, a highly upgraded development of the Lockheed T-33.

[3][4] However, technology passed the "T-Bird" by, and by the 1980s, it was clear that the world's air forces needed a more modern training aircraft.

[2] The highly modified and modernized aircraft was expected to cost about half of a new comparable trainer, such as the BAE Hawk and Dassault/Dornier Alpha Jet.

The Skyfox was marketed either as a complete converted aircraft from Boeing, or as a conversion kit, with the customer providing the T-33 airframe.

Other modifications included inboard wing leading-edge extensions, the replacement of the tip tanks with winglets, a new canopy with one-piece windshield, revised nose geometry to improve visibility from the cockpit and to fair into the T-33's lateral intakes, new tail surfaces with a mid-set tailplane (although the original wings were retained), and new avionics.

The result was a greatly improved maneuverability, range, endurance, and payload, plus the added overwater and hostile terrain safety of the twin powerplant configuration.

The Força Aérea Portuguesa (FAP) proposed that Oficinas Gerais de Material Aeronautico (OGMA) in Alverca would undertake the conversions, but insufficient orders were obtained from other nations to motivate Boeing to continue with the project.

[citation needed] It was originally planned to demonstrate the Skyfox at Farnborough International 1986, but the aircraft was tested at the time by the USAF.

For over two decades, the prototype was parked on the flightline at Rogue Valley International-Medford Airport in Medford, Oregon without engines or cowlings.