US 498th Airbase Group
The 498th Air Base Group was a military unit located on an unspecified Air Force base near Omaha, Nebraska, United States of America in 1969 as part of the Strategic Air Command. In that year, the  arrived in low Earth orbit above the base following a nearly catastrophic encounter with a black star which had displaced it in time.

Meanwhile, Technician  reported the RADAR contact, and his superior informed Air Defense Command, which scrambled  John Christopher, a fighter pilot, to intercept what was then believed to be a UFO. In one version of history, Christopher's aircraft was caught and crushed by the Enterprises tractor beam. Captain Kirk and Lieutenant Sulu infiltrated the 498th Air Base to retrieve the photographic and audio records of the incident that were recovered from the wreckage of Christopher's aircraft. Later, Spock devised a way to replay history that effectively erased the Enterprises presence altogether. Its brief appearance was doubtless logged as one more strange aerial incident.

Captain Christopher had been assigned to the 498th Air Base in 1968, and was therefore able to provide the Enterprise crew with detailed information on its layout, including the location of the record section and the photo lab. ()

de:498th Airbase Group
fr:Base 498 de l'US Air Force
Earth
Military units