G-50X rocket plane

The G-50X rocket plane was a type of aircraft flown on Earth in the 23rd century.

History and specifics
The G-50X was developed for atmospheric and orbital space flight by Trans-Global Aeronautics Research Corporation. In the 2260s, test flights were flown by famous test pilot Wallace Hawkins at Maribou Flats airfield in North America, overseen by Starfleet personnel.

In the middle of one test flight, after the airplane had left Earth's atmosphere, it was intercepted and hijacked by a, which stored the vessel in its cargo hold. The saucer then departed for the Collector's museum on Beton III.

When the saucer approached the Beton star system it detected and then attacked the starship USS Enterprise (NCC-1701). The Enterprise returned fire, disabling the saucer. A boarding party discovered the G-50X in a cargo hold and found Hawkins lying on the deck, either unconscious or dead. Kirk reported the events to Admiral Voysey at Starfleet Headquarters, who connected the G-50X theft with other mysterious aircraft disappearances.