* Union says ground crew strike has ended
* Strikes sparked by suspension of three workers
* More disruption could lie ahead, expert says
By Allison Martell and Susan Taylor
TORONTO, March 23 (Reuters) - Wildcat strikes that disrupted dozens of Air Canada flights ended on Friday when ground crews at airports in Toronto and Montreal returned to work, their union said, in a fresh reminder of the airline's tense labor relations.
The strikes were triggered Thursday evening when Canada's largest air carrier suspended three ground workers in Toronto allegedly for clapping derisively at Canada's labor minister as she walked through Pearson International Airport. The impromptu work stoppage later spread to baggage handlers at Montreal's Trudeau International Airport and briefly to Vancouver International Airport.
The minister has become the public face of the Conservative government's efforts to prevent any disruption of Air Canada service because of disputes between the airline and its unions. Ottawa maintains that any work stoppage would harm Canadians and hold back a still-recovering economy.
Earlier this month the government enacted a law sending the airline's separate disputes with the machinists and its pilots to binding arbitration. That prevents the machinists from carrying out a strike threat, and the airline from possibly locking out the pilots.
Under the circumstances, said George Smith, a Queen's University labor relations expert and former Air Canada executive, the airline could face more disruptions.
"I also see it happening in more subtle ways until things are resolved - employees can work to rule, they can not work overtime," Smith said.
Airport operations are returning to normal, said Air Canada, which does not expect further disruption.
"We have the injunction now and we would expect that it will be obeyed and there's not going to be any more issues like that," said spokesman Peter Fitzpatrick.
The wildcat strikes ended after a Friday morning arbitration meeting in which Air Canada agreed to reinstate 37 employees who had walked off the job to protest the suspension of three co-workers.
The three workers accused of harassing Raitt remain suspended with pay, pending an investigation, and could face more penalties, said International Association of Machinists and Aerospace Workers spokesman Bill Trbovich.
At mid-day message boards at the airport continued to warn passengers of delays and cancellations for Air Canada flights. Pearson's website said 82 Air Canada flights had been canceled and 37 were delayed.
Dan Giosa, a machinist union member at Pearson, said he wasn't working his shift on Friday because he was angry at Air Canada. He said he was unable to make ends meet on his current wages and recently had to move back into his parents' home because he could not get a mortgage.
"Eventually I have to get back to work, I've got no choice. I do work for a living," he said.
While some passengers at Pearson expressed anger at union workers, notably a man who was photographed spitting in the face of a baggage handler, others were sympathetic.
Gerry Rogers, a provincial legislator returning to collect baggage Friday morning after a futile two-hour wait Thursday night, said the ground crew suspension seemed "heavy-handed."
"I think the workers would rather be at work ... but the federal government has basically thrown away the rule book," said Rogers, a New Democratic Party member of the Newfoundland and Labrador legislature. The federal NDP, the official opposition party, is holding its leadership convention in Toronto over the weekend.
Raitt, who has taken a lead role in the government's efforts to prevent labor strife from grounding Air Canada, wasted little time on Friday morning in warning the wildcat strikers to get back to work.
She said that law enforcement authorities could step in to deal the strike if workers continue to disrupt services.
"The government of Canada is opposed to this illegal strike action that is disrupting travel for Canadians," said Raitt in a statement.
If the union's job action was later ruled by the Canada Industrial Relations Board to be an illegal strike, she said, employees could face fines up to C$1,000 ($1,000) a day, and the union up to C$100,000 a day.
But a spokesman for the board said it had never received an application regarding the wildcat strike.
Before the legislation Raitt pushed through earlier this month, she took the extra step of asking the CIRB to decide whether Air Canada is a service essential for Canadians' health and safety. That essentially blocks either a strike or lockout until the board issues a ruling, and that is expected to take months.
By pre-empting collective bargaining, government intervention has prevented Air Canada and the union from reaching long-lasting labor agreements, Smith said.
"The blunt instrument of legislation ignores the realities of the workplace and as bad as the adversarial system sounds to some people, the fact is that it actually resolves differences," he said.
The wildcat strikes on Friday and a spate of sick leave taken by pilots last weekend makes matters worse than a short-term strike, he said, because it creates uncertainty for the airline and its passengers.
Air Canada shares were unchanged at 82 Canadian cents on the Toronto Stock Exchange at mid-session. The stock has dropped nearly 19 percent year to date.