United Airlines said that the flight returned safely to Honolulu after a potential security concern was found written on a lavatory mirror. The airline said law enforcement met the aircraft and a security sweep was conducted. Customers onboard are being rebooked onto another flight that shall depart later on Wednesday.

The emergency at the bayside hub began about 8:30 a.m., when a passenger aboard Honolulu-bound Flight 15 was overheard "making a threat."