Air Canada and the Canadian Union of Public Employees reached a tentative collective agreement early Tuesday, ending a four-day strike by about 10,000 flight attendants that had effectively shut down the country’s largest carrier at the height of the summer travel season. The stoppage, which began on Saturday, forced the cancellation of roughly 700 daily flights and disrupted travel for more than 500,000 customers. Ottawa intervened over the weekend, issuing a back-to-work order under Section 107 of the Labour Code and directing the Canada Industrial Relations Board to impose binding arbitration, a directive the union defied until talks resumed late Monday with a federal mediator. Terms of the accord were not disclosed, but Air Canada had earlier proposed a 38 percent increase in total compensation over four years, including a 25 percent raise in the first year. The union said the tentative pact secures pay for on-ground tasks such as boarding that previously went uncompensated. Air Canada said it will begin rebuilding its network Tuesday evening and expects it may take seven to ten days to return to a normal schedule, with some additional cancellations likely during the reset. Customers whose flights were scrapped can request rebooking, credit or a full refund.