Chaos erupted at La Guardia Airport early Saturday after a Michigan man argued with a Spirit Airlines employee and then claimed he had a bomb, sources said.

Many passengers panicked when authorities swooped in and shut down Terminal B at about 7:40 a.m.

Kathy Rutledge, 65, of Texas, had just come up an escalator when she saw the scene.

“We saw big guns, SWAT teams,” Rutledge told The Post. “They started moving people out of the way. They were shouting, ‘Get back! Get back! Everybody head to the food court!’ ’’

John Park, 70, of Farmington, Mich., allegedly was arguing with an airline employee as he tried to buy a ticket, the sources said.

Park walked away, then returned, put a bag on the counter and told the employee he had a bomb, the sources allege.

The NYPD Bomb Squad investigated the bag and deemed it safe before reopening the terminal about two hours later. Park was arrested.