A Delta jet carrying 103 passengers to Reno returned to Salt Lake International Airport Thursday night amid what turned out to be unfounded reports of a possible explosion on board.

Flight 1577 departed from the airport at about 9:11 p.m. and was flying over the Ogden area when the pilot reported a "strange odor" and a "popping noise" in the left engine of the Boeing 737-200, said Fred Rollins, Delta's district marketing director.The pilot held over Ogden for a while and then returned to Salt Lake City, Rollins said. Though the pilot didn't report the incident as an emergency, at about 9:30 p.m. control tower personnel reported a possible explosion on board and called emergency crews to the airport.

The plane landed without incident, and no one was injured, Rollins said. Passengers were transferred to a different aircraft, which departed for Reno at about 10:20 p.m.

As they boarded their replacement jet, passengers commented they had heard the popping sound, but the aircraft's flight remained smooth.

Passengers Rich and Donna Bowden, who were on the way to Reno for their daughter's wedding, said everyone on the jet was calm when they heard they would be returning to Salt Lake.

"The pilot was real calm," said Rich Bowden. "He said there was a little problem and that we'd be turning back. They handled it real well."

Rollins said that the source of the popping noise hadn't been determined, but that the jet would get a thorough going-over at Delta's new $20 million maintenance facility and would likely be back in the air Friday.