Air Canada said it apologizes to its customers after reports emerged that passenger seats were dirty with vomit on a flight from Las Vegas to Montreal.

A woman who said she was one of the passengers on the August 26 flight wrote in a social media post that the flight crew "put coffee grounds in the seat pocket and sprayed perfume to mask the smell" of the vomit before boarding the plane.

"When passengers who appeared to be distressed tried to explain to the attendant that the seat and seatbelt were wet and that there were still visible remnants of vomit in their area, the attendant apologized profusely but explained that the flight was full and there was nothing they could do," wrote Susan Benson on Tuesday, August 29.

The flight from Las Vegas to Montreal takes over four hours. Benson wrote that passengers were given blankets, wipes, and more sickness bags. When they settled in, according to Benson, the pilot approached them and asked them to leave.

In response, the airline said it is "reviewing this serious matter internally and following up with customers directly."

Air Canada also wrote: "Our operating procedures were not followed correctly in this case," adding that it apologized to the affected customers.

The airline added: "It is clear they did not receive the level of care they deserve. We are in contact with them regarding this matter."