MONTREAL (AP) -- Air Canada said Wednesday it will begin a gradual suspension of flights to allow an orderly shutdown of the country's largest airline as it faces a potential work stoppage by its flight attendants on Saturday.

The airline said the first flights will be cancelled Thursday, with more on Friday and a complete cessation of flying by Air Canada and Air Canada Rouge by the weekend.

The union representing around 10,000 Air Canada flight attendants issued a 72-hour strike notice Wednesday. In response, the airline issued a lockout notice.

Air Canada said customers whose flights are cancelled will be notified and they will be eligible for a full refund. The company also said it has made arrangements with other Canadian and foreign carriers to provide customers with alternative travel options to the extent possible.

"We regret the impact a disruption will have on our customers, our stakeholders and the communities we serve," Air Canada CEO Michael Rousseau said in a statement.

On Tuesday, Air Canada said it had reached an impasse with the union as the two sides remained far apart in contract talks. The union has said its main sticking points revolve around what it calls flight attendants' "poverty wages" and unpaid labor when planes aren't in the air.

"Despite our best efforts, Air Canada refused to address our core issues," the union said in a bargaining update posted online.

The union rejected a proposal from the airline to enter a binding arbitration process, saying it prefers to negotiate a deal that its members can then vote on.