A fighter jet carried out what is known as a "headbutt maneuver" to get the attention of one particular civilian pilot, the U.S. military said.

Some of the planes were met by F-16 fighter jets operated by the North American Aerospace Defense Command (NORAD), and forced out of the airspace.

A NORAD fighter jet was deployed on July 5, to intercept a civilian aircraft that unlawfully entered restricted airspace over Bedminster, where President Trump was spending the holiday weekend.