What to know as Air Canada strike continues

Flight attendants for Air Canada say they're not ending the strike - despite a federal back-to-work order - throwing the airline's plans to resume flights up in the air.

The strike by more than 10,000 flight attendants for Canada's largest airline has stranded tens of thousands of passengers since flights were grounded on Saturday.

The Canadian Industrial Relations Board (CIRB) has deemed the strike unlawful and told the airline's staff to return to work.

It said that an expired collective agreement would be extended until a new one was agreed.

But union leaders said they would be willing to pay fines, or even face jail time, rather than return to work.

"If Air Canada thinks planes will be flying this afternoon, they're sorely mistaken," said Canadian Union of Public Employees (Cupe) president Mark Hancock on Monday.

Here's what you need to know.

When will Air Canada flights resume?

It's unclear.

About 500,000 customers' flights have been cancelled as a result of the strike, Air Canada said on Monday.

The airline had wanted to resume flights on Monday evening, but with flight attendants still striking, it remains to be seen when they will take off again.

The company already said it expected several days of disruption before scheduling returned to normal once flight attendants return to work.

Air Canada has said it will offer those with cancelled flights options including a refund or credit for future travel.

Why was the strike called off?

On Monday morning, CIRB told staff to return to return to work by 12:00 EDT (14:00 GMT) on Monday and called the strike illegal.

It said defiance by the Canadian Union of Public Employees (Cupe)of a back-to-work order on Sunday is "unlawful".

A collective agreement that expired on 31 March would be extended until a new one was agreed, Air Canada said.

Cupe president, Mr Hancock, said union leaders are willing to accept any penalties for its refusal to comply, including monetary fines and jail time.

It is unclear what the consequences will be.

Why did Air Canada cancel flights?

Flight attendants gave a 72-hour strike notice last week after contract talks reached an impasse. Soon afterwards, Air Canada began delaying and cancelling some flights.

By Saturday, Air Canada said it was forced to suspend "all operations" after workers voted to go on strike.

With the strike in effect, the airline announced it would halt flights on its Air Canada and Air Canada Rouge service.

Air Canada Express flights, which carry about 20% of Air Canada's daily customers, are not affected.

What led to the strike?

The Cupe union said the company was not addressing key issues such as wages and unpaid work.

It said it bargained in good faith with the airline for more than eight months.

The airline said it recently offered flight attendants a 38% increase in total compensation over four years, with a 25% raise in the first year.

But the union said the offer was "below inflation, below market value, below minimum wage" and would leave flight attendants unpaid for some hours of work, including waiting at airports ahead of flights or during the boarding process.

They said wages had not kept up with inflation, so Air Canada's suggested pay increase was "in effect, a pay cut".

Almost all of the attendants - 99.7% - voted to strike earlier this month. The company asked the government to intervene.

How did the government respond to the strike?

As the cancellations mounted, the Canadian government used its powers to force the airline and the union into binding arbitration, in an effort to minimise disruptions for travel and the economy.

On Saturday, Hajdu ordered Air Canada and Cupe into binding arbitration by invoking Section 107 of the Canada Labour Code.

"Despite significant supports from the government, these parties have been unable to resolve their differences in a timely manner," Hadju said.

"I am exercising this authority because it is critical to maintaining and securing industrial peace, protecting Canadians and promoting conditions to resolve the dispute."

The Canada Industrial Relations Board then issued a return to work order for 14:00EST (18:00 GMT) on Sunday, which the union defied.

Cupe accused the federal government of violating the charter rights of striking workers. They alleged that forcing an end to the strike will "ensure unresolved issues will continue to worsen by kicking them down the road".

In binding arbitration, an independent third party sets the terms of a contract in an agreement that is legally enforceable.

What to do if your flight is cancelled

Air Canada has said it will notify passengers if there is a change to the flight's scheduled departure time.

Customers whose flights are cancelled will be notified and will receive a full refund, the airline said. The company has also made arrangements with other Canadian and foreign carriers to provide customers alternative travel options.

If it's a round trip, return flights are not automatically cancelled in case the passengers reaches the destination.

Those bookings can be cancelled with no fees.