Alaska Airlines spokesman Tim Thompson told The Associated Press in an email that the flight turned back to Alaska "due to a passenger not following flight attendant's instructions."
"While no emergency was declared, the decision was made to return to Anchorage," Thompson told the AP.
A passenger on the flight told the AP that she didn't see the man, but she knew that something was going on Wednesday because flight attendants were going up and down the plane's aisles and put on rubber gloves.
She said she heard that a man "had taken off his clothes and he just wasn't in his right mind," according to the AP.
Thompson told KTVA that the man was escorted off the plane by law enforcement officers, although it was not immediately clear whether the man was facing charges.
The plane had 178 passengers onboard when it turned around. The incident delayed the flight by about five hours, according to KTVA.