With a pilots' strike averted for now, Air Canada passengers who rebooked their flights may be able to go back to their original bookings.

Air Canada and the Air Line Pilots Association reached a last-minute tentative deal Sunday, preventing the countrywide shutdown of nearly all operations that could've affected more than 110,000 passengers and disrupted tonnes of cargo, according to the airline.

"Air Canada flights will be operating as scheduled, and we're pleased to advise our valued customers that they can proceed with their travel as planned with the certainty that flights are operating normally," the airline wrote on its website Sunday.

Amid the threat of the strike, the airline had given customers the option earlier last week, through its goodwill policy, to rebook their flights under certain conditions.

Customers who rebooked can now change their flights back to the original booking within the same cabin class, free of charge, if there are available seats, the company announced in a press release Sunday. If there's only space in a cabin class different from their original booking, customers can upgrade and pay the difference.

The four-year collective agreement would affect more than 5,200 pilots at Air Canada and Air Canada Rouge if approved.

The airline said the details will remain confidential pending a ratification vote expected over the next month, and approval by the Air Canada board of directors.

In a statement Sunday, the union said the deal would generate approximately $1.9 billion in additional value for Air Canada pilots over the course of the agreement and represents progress on compensation, retirement and work rules.

With files from The Canadian Press