March 29 (UPI) -- Two pilots on different planes each spotted an unidentified object in the sky over southern Arizona last month, as they flew at about 37,000 feet.
The pilot of a Learjet reported the first sighting on Feb. 24 after he saw a bright object moving fast in front of and above their position.
"Was anybody above us that passed us like 30 seconds ago?" the pilot asked a ground controller. After receiving a negative answer, he added, "Okay, something did."
A few minutes later, an American Airlines pilot spotted the same object after a controller radioed to ask if he saw anything unusual in the sky.
"Yeah, something just passed over us," the American pilot responded, according to an FAA recording. "I don't know what it was."
"It was at least 2,000-3,000 feet above us," he added. "It passed right over the top of us.
"It was just really beaming light, or could have had a big reflection and was several thousand feet above us going opposite direction."
Authorities said it was likely a weather balloon -- but that hasn't stopped some from coming up with their own theories.
Earlier this month, a Defense Department video chronicled another sighting by U.S. Navy fighter pilots in 2015 while they were in the sky above the East Coast.
A Pentagon program to investigate military UFO sightings was shut down in 2012.