A Frontier Airlines plane was evacuated after staff found a gun magazine aboard in Denver — days after a flight struck and killed a trespasser on the tarmac at the same airport. Passengers deplaned from a Frontier flight from Denver to Phoenix on Sunday after staff made the startling discovery, a company spokesperson confirmed. Passengers were screened “as a matter of precaution,” and no actual firearms were found aboard. “Our preliminary investigation indicates that the magazine belongs to a law enforcement officer,” Frontier told The Post. It was the fourth chilling airport safety episode in a week. Security at Denver International Airport investigates a plane where a gun magazine was found aboard a plane on May 10, 2026. Denver7 A Frontier Airlines plane parked at a technical operations center; the airline has had two safety incidents in the space of a week, including one in which a plane struck a man on the runway.…