With an Air Canada strike looking increasingly likely, the airline has announced it is allowing passengers to rebook their travel plans to avoid the expected disruption.

But a work stoppage could be short lived, as Labour Minister Lisa Raitt said the government is ready to introduce back-to-work legislation drafted during the first round of labour negotiations earlier this year.

The airline's 6,800 flight attendants will be in a legal strike position at 12:01 a.m. Thursday morning after members rejected a tentative contract agreement on Sunday.

It marks the second time negotiators for the Canadian Union of Public Employees have reached a tentative agreement with the employer, only to have the flight attendants reject the contract.

Of the flight attendants who voted, 65 per cent rejected the deal.

Air Canada has issued a statement saying it hopes to avoid a work stoppage, but will try to maintain a partial schedule if the strike goes ahead.

However, the airline said it is now allowing customers who are booked to travel in the next six days, to change their dates for free.

According to the statement, passengers who are booked on flights from Oct. 10 to Oct. 15 can change their travel dates until Dec. 15 free of charge. That offer will be renewed every six days on a rolling window basis.

The government has said it won't tolerate a lengthy strike, meaning employees could soon be back at work in the event of a stoppage.

"I would highly recommend to both parties that they conclude some kind of deal that they believe can be ratified … It is their best interest to do so," Raitt told CTV News Channel Monday.

Raitt made it clear during the negotiation process that she was ready and willing to introduce back-to-work legislation if the two sides were unable to make a deal by the deadline.

She even had the legislation prepared ahead of time, though it was never used because the negotiators managed to settle on an agreement just hours before the deadline was reached.

However, the House of Commons is not scheduled to be in session this week, and MPs would have to be called back for an emergency session in order for a back-to-work bill to be passed any earlier than next week.

It's the second time the flight attendants have turned down a deal that their representatives negotiated on their behalf, thereby erasing weeks of work at the bargaining table.

The previous tentative agreement was rejected in August, after CUPE leaders said they were confident members would support the deal.

Duncan Dee, Air Canada's executive vice-president and chief operating officer, said he still had hope that a deal could be reached.

"We are perplexed and disappointed that two tentative agreements negotiated in good faith with and unanimously recommended by the democratically elected representatives of our flight attendants have failed to be ratified," Dee said in a statement. "Air Canada remains hopeful that a disruption can be avoided."

Jeff Taylor, president of CUPE's Air Canada Component, said the vote indicates union members are frustrated with the airline. The major areas of dispute between the two sides are wages, pensions, crew reset and working conditions.

Taylor cautioned the federal government against threatening or introducing another back-to-work bill in an effort to quash a strike.

"We ask the federal government, in the strongest possible terms, to respect our right to collective bargaining and not intervene unilaterally in this dispute," Taylor said.

Strike could harm economy, says Raitt

Raitt has openly said she believes the threat of looming back-to-work legislation helped motivate union representatives to reach a deal with the airline.

"The government has already indicated what its plans were in the event of a work stoppage last time," Raitt said. "That legislation is still alive and available to us."

Responding to critics who say that the government should stay out of the labour talks and let the two sides come to an agreement, Raitt noted that a potential strike at the airline could be detrimental to the economy at a time of uncertainty.

"We have a situation here, where you can easily see that the parties are simply not coming to an agreement that can be ratified themselves."

Raitt added that the contents of the legislation remain under wraps, so it's not clear to either side if they could gain an advantage by waiting for Ottawa to force the issue.