Mike Van Dijk says the pilot of the flight to Saskatoon from Toronto first announced Monday night that something had disappeared from the plane.
"That we had lost something," Van Dijk said. "And, at first, it kind of seemed like something had fallen off the plane."
Officers next told everyone that they wanted the thief to come forward.
"'You can either tell us who it is right now, or we're going to have to go through all the bags and it's going to take quite a while,'" Van Dijk recalls an officer saying.
An embarrassed man at the back of the plane then turned over his bag and the missing megaphone crammed inside.
Police have said an item was snatched from the plane's kitchen but gave no other details.
Jake Michael Piasentini, 29, of Saskatoon was in court Tuesday to face charges of theft and mischief. He was released from custody and is to appear in court again in two weeks.
A Crown lawyer said it's believed alcohol was a factor in the case.