WestJet Airlines’ check-in services have been restored, after a temporary system outage caused flight delays and snarled travel across Canada Thursday morning. System outages affected both WestJet Airlines and air traffic control agency NAV Canada on Thursday, with travellers on social media reporting long lines and confusion at airports.

On Thursday afternoon WestJet spokeswoman Morgan Bell said travellers were still being encouraged to arrive early and check their flight status before heading to the airport. She said the airline was still experiencing issues with its self-serve baggage drop at Calgary, Ottawa, Saskatoon and Halifax airports.

NAV Canada, the not-for-profit corporation responsible for air traffic control in Canadian airspace, said it was experiencing disruptions in western locations Thursday due to a service outage with its third-party telecommunications provider, Zayo.

Zayo spokesperson Karen Modlin said the outage amounted to a disruption of two key fiber lines managed by one of the company’s underlying fiber providers in Canada and was caused by a train derailment Wednesday evening.

“We have rerouted a significant volume of traffic via other routes so that our customers can begin resuming normal operations,” Modlin said, in an email to The Canadian Press.

“We regret the inconvenience this has caused for our customers and air passengers, and our top priority is the safety of everyone involved.”

NAV Canada spokesman Brian Boudreau said air traffic control reduced the flow of departures and arrivals temporarily in some locations as a result.

He later added that services are “returning to normal.”

The outages Thursday are exacerbating what has already been a frustrating summer for Canadian air travellers.

Airlines and airports have been struggling to cope with a massive travel resurgence in the wake of the lifting of COVID-19 restrictions, and staffing issues at carriers and federal agencies have resulted in flight cancellations, baggage delays and endless queues.