Andrew Alessi forced his way past two American Eagle agents and ran down the jet way to the aircraft around noon, half an hour before it was scheduled to start boarding, said Baton Rouge Metropolitan Airport spokesman Jim Caldwell said.
"He stayed there for several hours while police and FBI negotiated with him. He eventually came out voluntarily," Caldwell said.
Alessi bought his ticket at the airport shortly before boarding, cleared security with a piece of carry-on luggage and didn't have any weapons, he said. The flight, which was headed to Dallas/Fort Worth, was canceled and passengers were being accommodated, he said.
No other flights were delayed.
FBI spokesman Kyle Hanrahan said Alessi, of Baton Rouge, likely will be charged with interfering with a flight crew.
"I think he was distraught. I don't know specifically why he did what he did," Hanrahan said.
A Baton Rouge Police Department spokesman said Alessi is in federal custody and will be booked into the East Baton Rouge Parish Prison when they are done with their investigation.
No one answered the phone at a number listed for Alessi and the voicemail box was full. American Airlines spokesman Matt Miller said the airline will be reviewing their security procedures going forward.