Air Canada made this announcement:
In response to the strike vote mandate given by WestJet’s pilots, Air Canada today announced it has now added capacity on key transcontinental routes by up-gauging aircraft on certain flights from its primary global hub in Toronto to Vancouver, Calgary, Edmonton, Winnipeg, Montreal, Ottawa, Halifax, from Vancouver to Calgary, Edmonton, and from Calgary to Montreal.
Copyright Photo: Air Canada Boeing 777-333 ER C-FIVW (msn 42218) LHR (SPA). Image: 941740.
Air Canada aircraft slide show (current livery):