Looks like UA1 and UA3 were recalled to ORD when the Hawaii earthquake happened (around 10am PDT). Other UA flights in the air continued while flights that had not departed were cancelled. According to LAX area news and Flightaware tracks, UA is the only airline that had mass cancellations; other carriers either continued to Hawaii or delayed their departures.
Is it likely that United, with its long history of scheduling UAL1 KORD/PHNL, would fly a 747 as UAL1 between Blythe, CA and Mesa, AZ at midnight? There are no plane graveyards in Mesa.
The issue of UAL1 in southwest discussed here. But really no resolution as to who owns the 747’s and what they are doing flying from small port to port.
This sounds all-to-similar to the phantom AA 747s and the NW An-124 discussed last week. There’s either a glitch with the FAA (or FA), or someone in Arizona needs to learn how to file a flight plan!!