Sunwing Airlines says it has been able to subcontract other carriers to help clear a backlog of stranded passengers after a cyber breach at one of its service providers delayed dozens of flights by days.

“Thank you WestJet, Air Transat and Nolinor Aviation for your help in getting our passengers to their destinations!,” the airline tweeted Wednesday afternoon.

The airline said that it continues to manually check in passengers for their flights and is working to do so as quickly as possible.

Sunwing CEO Mark Williams told CP24 in an interview Tuesday that Airline Choice — the third party vendor responsible for a system which checks in passengers and provides background info about them — was hacked, resulting in the outage.

While other airlines have been affected by the outage, Sunwing is the only Canadian airline which uses the vendor, William said.

More than 1,000 customers have been stranded abroad because of the problem and many others have been stranded at Canadian airports.

It is not yet clear whether any passenger information was accessed in the breach and there is no timeline for a fix.

The outage began on Sunday and stretched into its fourth day on Wednesday. 

Passengers who have been stranded or had their holidays truncated or cancelled because of the problem have criticized the airline for not communicating well.

One stranded passenger told CP24 that the airline only started providing information once frustrated customers “got in their face.”

William said that Sunwing has been relaying information through its Twitter account and website and through megaphones at the airport.

He said Tuesday that any passenger whose flight has been delayed by more than three hours would receive financial compensation. The airline is also allowing those whose flights were delayed between April 19 and April 22 to delay their trip as far as June 23 if they wish to do so.