The incident occurred Saturday on a United Airlines jetliner en route from Washington, D.C., to Las Vegas. The plane, which had more than 100 people aboard, was diverted to Denver International Airport.
FBI spokeswoman Kathy Wright said a passenger tried opening one of the front doors of the airplane and may have tried to open the cockpit door before passengers restrained him. The man was taken into custody, questioned and released for a medical evaluation, she said.
Authorities will decide on charges after reviewing the incident, Wright said.
The man's last known address was in New York state. Wright declined to release additional information, including the man's name, citing medical privacy and that the matter remained under investigation.
Passengers told Las Vegas television station KTNV-TV after the plane landed that the man said he was from California and was on the wrong plane.