An Air Canada Boeing 777 is refuelled in this July 28, 2011 file photo. (REUTERS FILES/Tim Wimborne)

Passengers hoping their early Wednesday flight from Halifax to Toronto would take off on time were let down by a cat who escaped in the cabin of the plane and entered the cockpit, causing a more than four hour delay.

"From what I can understand, a passenger went on board the aircraft into the cabin with the cat in a pet carryall, and somehow it got loose in the cabin, found its way into the cockpit of the aircraft and then got itself down somewhere in the cockpit where it couldn't be reached," Halifax International Airport Authority vice-president Peter Spurway said Wednesday, not long after Air Canada flight 603 had finally taken off.

Air Canada brought in maintenance workers, who eventually removed panels inside the cockpit, Spurway said. The feline was finally retrieved three hours after the flight was scheduled to take off, he said.

The panels in the cockpit had to be reassembled and the passengers had to get back on board, Spurway said. The flight, scheduled to take off at 5:40 a.m., didn't leave until just before 10 a.m.

Spurway could not confirm whether the cat and its owner were on board the flight.

"Obviously for the passengers this is going to cause some disruption," he said. "A lot of people get on that flight to do business in Toronto for the day, or to connect westward."

Spurway said cat-related delays are not at all common.

"In the cat-loose-in-airplane-in-cockpit file, we have one entry, and that's this morning."