Air Canada cancelled more than 70 flights from major Canadian centres today after some pilots called in sick to protest being forced back to work by federal legislation.
Numerous flight delays were also reported across the country.
Air Canada issued a Canada-wide travel alert, warning that "airport disruptions" could affect flights all day and into the weekend.
"It appears a small group of pilots are engaged in an illegal job action," said Air Canada spokesman Peter Fitzpatrick. "There's been a higher than normal level of pilots calling in sick — and as a result we've had to cancel some flights today."
The Air Canada Pilots Association, which represents 3,000 pilots, urged members to report to work and ignore "a small group" of pilots who want colleagues to call in sick to show dissatisfaction with management after contract talks broke down.
Capt. Jean-Marc Bélanger, head of the pilots association, said the union didn't initiate or sanction the job action.
Last month, the federal government referred Air Canada's two labour disputes to the Canada Industrial Relations Board, a move that prevents a work stoppage and effectively forced the pilots back to work.
Fitzpatrick said "the vast majority of pilots" were showing up for work. "There's just a small group today that has decided to engage in this illegal activity."
On an average day, he said, the airline has about 1,500 flights. "So it's confined. But nonetheless, it does cause disruption for our customers and we're working hard to get people to their destination as soon as possible."
Fitzpatrick said the airline has instituted a "flexible" booking policy for Friday and Saturday, allowing customers to change flights to a more convenient time at no extra cost.
At Montreal's Trudeau airport Friday morning, there were a few flight delays and cancellations but no major problems. Halifax airport also reported few issues, with one cancellation reported.
There were some delays in Winnipeg, and two flight delays in Saskatchewan — both in Regina.
Union 'incredibly frustrated'
Bélanger, head of the pilots association, said in a note to pilots that the union and its members could face fines for failing to work during the arbitration procedures of the Protecting Air Service Act.
Still, he added: "We are not surprised by your strong responses to the corporation's recent correspondence. We are, like you, incredibly frustrated by management's refusal to negotiate with us and by the collusion with the federal government forcing us into a process that we are actively contesting."
Passengers were predictably annoyed at the disruptions.
"We've got hotel reservations and people waiting for us in Vancouver, and it's kind of screwed it all up," Jane Monaghan told CBC News at Toronto airport. She had just arrived at the airport to find her flight cancelled.
Speaking to CBC's Carole MacNeil on Friday, Conservative MP and parliamentary secretary to the minister of transport Pierre Poilievre defended the government's move to pass the back-to-work legislation as necessary "to protect the Canadian economy from the debilitating effects" of an airline shutdown.
"We did exactly the right thing, and to what extent there are disruptions today, those disruptions would have been far worse, far bigger, and far more consequential had we not acted," he reasoned.
Memo warns of market risk
The government's top priority was ensuring that travellers reach their destinations, Poilievre said, adding that the decision on whether the disruptions amount to wildcat strike activities will be ultimately left to the Canada Industrial Relations Board to decide.
"Certainly, our message to the pilots involved is to get back to work, get the planes in the sky, get passengers where they need to go," he told reporters earlier in the day.
In a memo sent to members of the pilots union on Friday, Air Canada Pilots Associaton President Capt. Paul Strachan said he had forwarded a report to stock analysts expressing extreme concern over corporate management at the airline.
He said the message was for stock analysts, academics and governance advisors. A copy of the missive, obtained by CBC News, states that shareholders should be worried about the airline's continuing "downward spiral" amid rising fuel costs and an economic downturn.
"I am taking the unusual step of alerting fellow shareholders, those who follow Air Canada and those who follow corporate governance issues in Canada that the corrosive internal environment being created at the airline raises serious questions about its long-term viability," Strachan writes, accusing executives of taking "huge personal financial rewards" while the company's shares hit a 52-week low.
With files from The Canadian Press