Flight 811 bound for Phoenix was taxiing from Gate 18 to the runway about 8:30 p.m. when a threat of a possible explosive or hazardous material was called in to a law enforcement agency, according to Lt. Joe Balicki of the Orange County Sheriff's Department.
At about the same time, a similar threat was received about two Southwest planes at Phoenix's Sky Harbor Airport. Both flights originated from John Wayne Airport. Nothing was found on those planes either.
The plane at John Wayne Airport was diverted to an isolated area of the airport, where passengers were deplaned. A bomb squad and K-9 unit were called in to investigate.
According to a Transportation Security Administration spokesperson, Southwest deemed the threats non-credible.
The FBI is investigating the threat.
The passengers of Flight 811 were waiting to catch another flight to Phoenix in the morning.