Southwest Airlines opens investigation into pilot who announced 'Let's Go Brandon' on flight

Southwest Airlines says it has opened an internal investigation following a report that one of its pilots said "Lets Go Brandon" over a plane's public address system during a flight.

"Southwest does not condone employees sharing their personal political opinions while on the job," the company said over the weekend.

"Southwest is conducting an internal investigation into the recently reported event and will address the situation directly with any Employee involved while continuing to remind all Employees that public expression of personal opinions while on duty is unacceptable."

On a flight Friday from Houston to Albuquerque, New Mexico, a pilot reportedly ended his greeting to passengers with the phrase that has become code for "F--k Joe Biden." 

The incident was initially reported by the Associated Press, which had a reporter on board the flight. 

Following the incident, the union that represents United Airlines pilots circulated a memo saying that in-flight radio frequency transmissions are "not to be used as a personal pulpit."

The phrase became instantly popularized last month when an NBC reporter interviewing NASCAR driver Brandon Brown mistakenly suggested on camera that the crowd was chanting "Let's go, Brandon," when in fact they were chanting "F--k Joe Biden." 

Since the viral interview, the phrase has been employed with a humorous tone across right-wing media, by members of conservative culture and by lawmakers.