A man who had missed his flight made a bomb threat that forced a Memphis-bound plane to return to Seattle-Tacoma International Airport on Wednesday, the Transportation Security Administration said.

"The plane was brought back, erring on the side of caution, after he made that threatening statement," TSA spokeswoman Jennifer Peppin said.

The man was taken to a holding facility at the airport police department's headquarters after telling a gate agent there was a bomb on Northwest Airlines Flight 980 shortly after the plane left Seattle around 12:33 p.m., airport spokeswoman Terri-Ann Betancourt said.

"After interviewing him, they said they do not believe it was a credible bomb threat," Betancourt said, adding "it was clear he wanted the plane to come back."

The man, who was traveling with a group, was never on the plane. He initially said he had no luggage on the aircraft, then later told authorities he had checked luggage under someone else's name, Betancourt said.

The plane, an Airbus A320 with 142 passengers and 5 crew members on board, returned to the airport around 1:15 or 1:20 p.m., Betancourt said.

Passengers remained on the plane for more than an hour while police tried to determine how extensive a security sweep was needed. Around 3 p.m., passengers were taken off the plane and all luggage was removed so bomb-sniffing dogs could search for any traces of explosives, Betancourt said.

Betancourt noted it's a federal offense to make a threat against a commercial aircraft but said she would not release any information about the man being questioned unless he was booked into jail.

In an e-mailed statement, Northwest spokesman Roman Blahoski said the airline "apologizes to its customers for the inconvenience and expects flight 980 to depart Seattle as soon as possible."