MONTREAL -- Air Canada and WestJet are taking their domestic rivalry to London with both companies now adding flights to Gatwick Airport next year.

The country's largest carrier, which already flies to Heathrow Airport from eight Canadian cities, announced Thursday it will add flights from Toronto to Gatwick on its leisure subsidiary Rouge next summer.

Benjamin Smith, president of passenger airlines, boasted that Air Canada (TSX:AC) will be the only Canadian carrier servicing multiple airports in the London area.

"Air Canada Rouge is ideally-suited to serve London-Gatwick, with its focus on leisure travel and provide easy access to southern London," he said in a news release.

The move comes several days after Calgary-based WestJet (TSX:WJA) said Gatwick would be its first transatlantic destination for its wide-body Boeing 767s. That service is slated to start next spring but the originating airports haven't been disclosed.

Bob Cummings, executive vice-president commercial for WestJet, said last week the planes will allow service to England from anywhere in Canada and to other international destinations. The Canadian airports will be determined this summer, he said.

WestJet currently uses its Boeing 737 planes to Dublin, Ireland from St. John's, Newfoundland and Labrador, and to Glasgow, Scotland, from Halifax.

Canada's largest domestic airlines fiercely battle on fares and other charges. They both introduced checked bag fees around the same time. As WestJet expanded its Encore regional service, Air Canada has moved some Jazz-operated Q400s to similar routes.

Air Canada also said Thursday that it will introduce year-round service on its mainline carrier between Montreal and Lyon, France. The airline will service the country's second-largest city, along with Paris and Air Canada Rouge flights to Nice.

Montreal airport authority president James Cherry said the flights to Lyon supports Trudeau International Airport as a hub to French-speaking Europe.

Air Canada said it will operate up to five times weekly to Lyon beginning next June and seven times weekly to Gatwick starting in May.