Air Canada and its customer service and sales staff continued talks on Monday against a looming strike deadline, with pensions and wages as the sticking points.

The sales and service agents could walk off the job at 12:01 ET if there's no deal.

Canadian Auto Workers president Ken Lewenza said the union, which represents the 3,800 workers, has tentatively agreed with the airline on some contract issues, but the two sides remain far apart on pensions and wages.

"We did a lot of work, but it just seems to me that we should be moving a little bit quicker than we are right now," Lewenza said.

Air Canada has downplayed the potential impact of a strike and said it will continue to operate a "full flight schedule" if the workers walk out.

Lewenza said the union is waiting for a response to its Sunday proposal, which could avert a walkout.

Air Canada customer service and sales staff are threatening to walk off the job if the airline doesn't budge on key concessions in their contract negotiations. (Andrew Vaughan/Canadian Press)

Lewenza said the union's proposal, which he declined to detail, would provide members with pension security and wage increases after a decade of uncertainty.

He said he's optimistic that a deal can be reached but acknowledged there's "a huge gap" between the two sides on these key issues.

'10 years of significant sacrifices'

"The demands on the pensions have diverted a lot of our attention, but at the end of the day our members have had 10 years of significant sacrifices," he said.

"Now it's time to make some progress, (and) wages are a big key to getting an agreement."

The company and the union say they are committed to reaching a deal, but there's been no sign of an agreement. The union served a 72-hour strike notice on Friday, allowing them to walk out 12:01 a.m. Tuesday.

Be prepared Air Canada is urging passengers to avoid delays in the event of a strike by taking these steps: Check in for flights online. (There's a tutorial offered at its website.)

Avoid travelling with luggage.

Arrive at the airport well ahead of deadlines.

The strike threat throws the travel plans of thousands of Canadians into disarray, though the airline has tried to reassure customers that it will continue to operate unimpeded.

"We're getting a lot of questions from the consumer, and we're looking for the same information the consumer is looking for," travel agent Jonathan Carroll, of itravel2000, told CBC News. "The only thing we've heard from Air Canada is, 'We have a contingency plan.' Unfortunately, that's not good enough. What we need is detail with the contingency plan."

Jamie Ross, who heads the Canadian Auto Workers local representing the workers, said the big sticking point is changes the airline has proposed to workers' pensions. Air Canada was forced into creditor protection from April 2003 to September 2004 partly because of its pension deficit.

Air Canada spokeswoman Isabelle Arthur said the company does not want to go into details about the pensions issue.

"We're looking at a pension plan where 26,000 active employees are sustaining 29,000 retired Air Canada employees, on top of a big deficit and repayments due for 2014, so we have to find a solution that ensures that Air Canada remains a viable company," she said.

Arthur said passengers should try to arrive at the airport a bit earlier than the usual deadlines and to refrain from checking baggage. Passengers were also urged to check in online (a tutorial offered at Air Canada's website).

Federal Labour Minister Lisa Raitt has said she's concerned about the potential impact of a work stoppage on Canadians and on Canada's economic recovery.

The minister couldn't be immediately reached, however, to comment on whether the Conservative government would be open to imposing back-to-work legislation.

Lewenza said he doesn't believe such action is warranted.

"I don't see this as an essential service, but the federal government does have a majority government and obviously they can basically do what they want to do but they should let the bargaining process work itself out."