The video shot from a Los Angeles TV news helicopter has baffled authorities. The FAA claimed its radar replays did not detect anything. NORAD did not monitor any missile activity and Vandenberg Air Force base had no planned rocket launches.
The plane theory is being backed by a prominent physics professor.
"It seems to change direction. Ballistic missiles don't do that. It doesn't accelerate. Ballistic missiles accelerate," Dr. Michio Kaku at City University of New York explained. "This is traveling at a constant velocity and it's going in the wrong direction. Ballistic missiles go east to west. This one seems to be going north and south."
Scientists say the appearance of a missile launch could be an optical illusion because if you look at a plane from a certain angle as it travels away from you, the contrails could make you think the object was going up like a rocket.
So far, it is just a theory.