Sunwing Airlines Inc. says thousands of passengers remain stranded and the start of vacations delayed for others as the company continues to struggle with a technical problem that has grounded flights.

The Toronto-based company says about 15 out of the more than 40 scheduled flights have been processed since the technical issue first surfaced.

Sunwing says its check-in systems provider continues to experience a system outage.

It says Airline Choice is working with relevant authorities to find a solution as soon as possible and is processing flights manually, subject to airport restrictions, curfews and required crew reassignments.

Some of the planes are waiting to return to Canada, which has delayed the start of vacations for other travellers.

Sunwing apologized to passengers 鈥渨hose travel plans have been impacted鈥� and urged them to sign up for flight alerts on its website at Sunwing.ca.

鈥淥ur team has been working day and night to find alternate ways to get customers to their destination or on return flights home,鈥� it said in a news release.

The tour operator has said the problem also affected other airlines, snarling their traffic as well.

鈥擳he Canadian Press