"Aircraft standing on their runway have always been vulnerable," said Frederik Mertens, a strategic analyst with Dutch research organization, TNO.

For some reason, the United plane made a wrong turn and went left into the SkyWest flight's path. This triggered an alert and the SkyWest crew pulled an evasive maneuver to avoid a collision.

The USS George Washington returned to its home port in Japan in November for a forward-deployment in the western Pacific Ocean.