The "Kinross Case", so called for the name of the air force base (AFB) from which the plane departed, involves the disappearance of a fighter jet and its crew, pilot Felix Moncla and radar observer Robert Wilson, sent to investigate an unknown object that was tracked on radar.

This is a photograph of a F-89 Scorpion fighter jet.

The history of the Kinross Case began on November 23, 1953. A US Air Force F-89 jet fighter was scrambled from the Kinross AFB in Michigan. The plane known as the Scorpion was sent on an "active air defense mission" to intercept an "unknown object." Speculation as to the identity of the object has been the subject of debate for over 50 years.

American officials claim that the object was simply a Canadian aircraft, while Canadian officials deny the claim, citing that there were no Canadian aircraft in the vicinity at the time of the incident.

The following is extracted from the official accident report:

Aircraft took off at 2322 Zebra 23 Nov 53 on an active Air Defense Mission to intercept an unknown aircraft approximately 160 miles Northwest of Kinross Air Force Base. The aircraft was under radar control throughout the interception. At approximately 2352 Zebra, the last radio contact was made by the radar station controlling the interception. At approximately 2355 Zebra, the unknown aircraft and the F-89 merged together on the radar scope. Shortly thereafter, the IFF signal disappeared from the radar scope. No further contact was established with the F-89. (The next 16 or so letters as well as the entire next sentence have been blacked out by Air Force censors) An extensive aerial search has revealed no trace of the aircraft. The aircraft and its crew are still missing.

Radar operators claim that the F-89 and the unknown object seemed to merge on their radar screens. At about the same time as the "blips" seemed to collide, both voice and identification friend or foe (IFF) contact were lost. According to reports, after the two objects came together, only one object, the original rogue object remained and it appeared not be affected as it continued on its original course and speed.

A large scale search was immediately launched. It's important to note that the aircraft was lost in late November and although the weather was stable, it was winter, snow covered the ground and the water of Lake Superior was freezing.

 

Sources:

http://en.wikipedia.org/wiki/Felix_Moncla
http://listverse.com/2011/03/14/top-10-people-who-vanished-in-airplanes/
http://www.ufobc.ca/kinross/