The threat against United Flight 934 was made from a pay phone about 6 p.m., sources told KTLA partner the Los Angeles Times.
The Boeing 777 was set to leave for Heathrow Airport shortly before 6 p.m., according to flight reports. The flight was at first delayed but was cancelled sometime after 8:30 p.m.
The plane was taken to an isolated area at LAX, and a bomb squad used dogs to search the aircraft, the Times reported. Airport police later told KTLA that nothing dangerous was found on the plane.
The FBI, Los Angeles Police Department and Los Angeles Airport Police responded to the scene.