MONTREAL - Air Canada won an order requiring its pilots to end "illegal" work stoppages Friday after labour unrest earlier forced cancelled flights, but Canada's largest airline could still face a costly consumer backlash.

Air Canada said late Friday it is preparing to resume its full flight schedule for Saturday following the cancellation of about 75 flights due to a spate of pilots calling in sick.

The airline said the Canada Industrial Relations Board granted an order declaring that certain pilots were engaged in an illegal strike.

The order calls on the Air Canada Pilots Association to take all reasonable steps to end the illegal strike and to pressure all participating pilots to return to work immediately, the airline said.

It was the third labour disruption at the airline in less than a month and industry experts said the uncertainty could discourage customers from choosing Air Canada (TSX:AC.B) during the busy summer travel season.

Air Canada's chief operating officer Duncan Dee said Friday that the airline was able to accommodate nearly all of the passengers on alternate flights, but added he recognizes the "inconvenience this job action has caused to our customers.

"We thank them for their patience and loyalty as we re-double our efforts to restore their confidence in Air Canada," he said in a statement.

"The vast majority of Air Canada's pilots reported to work today and performed their duties as the true professionals they are. I would like to thank them and all other Air Canada employees for getting our customers to their destination safely and as quickly as possible."

Friday's disruption forced thousands of unlucky Air Canada passengers to mark Friday the 13th unable to arrive at their destinations as planned.

More than 60 flights were affected at Toronto's Pearson International Airport and schedules were also disrupted in Montreal, Ottawa, Vancouver, Calgary, Edmonton and Winnipeg.

"I'm not impressed and it probably will make me look for alternates like West Jet," said Martin, a Burlington, Ont., resident who would only give his first name at Montreal's Trudeau International Airport.

"The last time I flew a couple of weeks ago, the flight got cancelled about an hour before take off so I had to scramble and find an alternate."

The 36-year-old Air Canada (TSX:AC.B) passenger said disruptions will frustrate anyone who travels and probably damage the airline's reputation.

The latest cancellation also prompted travellers and the Canadian public to vent their anger on social media.

"The bottom line, people? Just don't fly Air Canada," Jeremy Foreshew said on Twitter.

Capt. Paul Strachan, president of the Air Canada Pilots Association said he's not surprised that frustrated employees could take such moves on their own when their rights have been trampled on by the federal government.

"The way this is headed it could end up at a point where the pilots are going to take matters into their own hands and there'll be questionable ability of any party to affect outcomes, including my own," he said in an interview.

With arbitrators expected to be announced as early as next week, it's time for all sides to re-examine their strategies to avoid the possibility of protracted unrest, said Strachan, who is fighting a reprimand over comments he made about airline safety.

The arbitrators will have 90 days from appointment to hand down their decision.

In March, federal Labour Minister Lisa Raitt referred the airline's disputes with the pilots and with Air Canada's 8,600 ground crew to the CIRB.

A back-to-work bill was passed in mid-March but some ground workers staged a wildcat strike on March 23 that affected several Air Canada flights.

Flights were also cancelled March 18 when the airline faced runway problems at Pearson airport and pilots called-in sick. It was followed a week later by a wildcat strike by ground staff in Toronto.

The Protecting Air Service Act removed the right to strike or lock out and ordered both disputes to be settled by arbitration. Employees can be fined up to $1,000 and the union up to $50,000 for contravening the law.

Industry observers said Friday a lack of details about whether future flights would be impacted increases uncertainty for all of its passengers.

"It's really a no-win situation (for the airline)," said Gabor Forgacs of the Ted Rogers School of Management.

He said Canada's largest air carrier faces a real danger that passengers may switch to other airlines because of uncertainty about when labour disruptions may end.

"If travellers are concerned they don't mind paying different fares if they have certainty that the air carrier will take me where I need to go," the Ryerson University associate professor in an interview.

Isabella Caporici of NDG Travel in Montreal said the airline desperately needs to resolve its labour woes because some clients have already sworn off Air Canada.

"I have had clients that say 'Forget it I don't want Air Canada, I don't want to be involved in their hassles,"' she said in an interview.

The airline is most vulnerable where passengers have a choice of carriers like WestJet Airlines (TSX:WJA), Porter Airlines or other carriers.

However, some passengers have no choice where Air Canada offers the only service, including direct flights, she noted.

The country's largest carrier and its regional partners operate 1,500 flights a day, including 660 by the mainline carrier.