Geoffrey McGann, 49, was taken into custody Thursday at about 7:30 p.m. at Oakland International Airport before he boarded a flight heading to Los Angeles, the Los Angeles Times reported.
Sgt. J.D. Nelson of the Alameda County Sheriff's Department, said McGann placed a coat and an unusual watch in a plastic bin bound for the screening machine. The watch included a toggle switch, wires and a circuit board.
"Apparently he was wearing it and took it off to go through the screening process," Nelson said.
McGann had "all the components" to make an "improvised explosive device," except for the material that would have actually exploded, Nelson said.
Nelson said McGann was also dressed oddly, was wearing shoes two sizes too big, and had no checked bag.
"When you add it all up, it didn't add up," Nelson said.
McGann told authorities the watch was an art piece and said he wears oversized shoes because they are supposed to make him look taller.
"He does do art kind of stuff, but what reasonable person would bring a watch like that into an airport and think that's OK?" Nelson said. "You may have a toy gun as art, but would you bring it to the airport?"
Officers arrested McGann on suspicion of possession of materials that can be used to make a destructive device. He was being held Friday in lieu of $150,000 bail.
The incident delayed flights for about 20 minutes.