The airline's online departures schedule for Pearson International Airport in Toronto showed just a few flight delays.
Airline spokesman Peter Fitzpatrick said while weather, a fire at Pearson and other factors affected operations over the weekend, "some impact was the result of a higher-than usual pilot book-offs."
Air Canada said Sunday that it had asked the Canada Industrial Relations Board to intervene, saying it could not "condone such activities as part of industrial action to disrupt our operations."
The pilots' union did not immediately respond to requests for comment.
Air Canada is in the middle of a bitter labour dispute with its pilots that prompted the federal government to step in earlier this month.
In the face of the airline threatening to lockout its pilots and ground crew warning they might strike, the federal government referred the matter to the Canada Industrial Relations Board and also passed back-to-work legislation last week that referred the disputes to arbitration.
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