A trucker claims to have seen the heavily guarded convoy, with a triangular-shaped craft in tow, at night just about 100miles from the top-secret US Airforce base as the crow flies.
TR-3B is alleged by conspiracy theorists to be a secret "black project" spy craft of the US Government that can be flown into space.
The allegations are that these crafts are created at top-secret military bases like Area 51, in Nevada, by reverse engineering alien technology.
Others claim they are actual UFOs flown by aliens visiting Earth.
The man has filed a report about the sighting to the US-based Mutual UFO Network (MUFON), the world's largest organisation dedicated to UFO and alien research.
He said he was driving north on route I-15 between Baker and Primm, California, at 11pm on Thursday, February 9, when he had the shocking experience.