Prime Minister Mark Carney said the response from Air Canada following the LaGuardia plane collision that killed two of the airline's pilots shows "a lack of compassion", after the CEO released a condolence message in English only.

Canada's official languages are English and French. One of the pilots killed, 30-year-old Antoine Forest, is from French-speaking Quebec.

"We live in a bilingual country, and companies like Air Canada particularly have a responsibility to always communicate in both official languages," Carney told reporters on Wednesday.

Air Canada's CEO, Michael Rousseau, was summoned to Ottawa to answer for his unilingual message. The BBC reached out to Air Canada for comment.

Rousseau, who has been criticised before for not speaking French, is facing calls for his resignation, most vocally from Quebec Premier François Legault.

Forest and the other pilot, Mackenzie Gunther, were killed when an Air Canada plane collided with a fire truck on Sunday night at LaGuardia airport in New York shortly after landing.

The flight had come from Montreal, Quebec. Dozens of passengers were injured, and six remain in hospital, Air Canada said on Tuesday.

Shortly after the accident, Rousseau released a video statement on X expressing "deepest sorrow for everyone affected".

"We know this is a difficult day for everyone, including all of us at Air Canada," he said. The video included subtitles in English and French.

The statement caught the attention of Canada's parliamentary Committee on Official Languages, who summoned Rousseau to "explain himself" before MPs on why his message was released in English only.

The message, the committee said, is "incompatible with the obligations set out in the Official Languages Act and the expectations of the Canadian public.".

Rousseau has until 1 May to appear before the committee.

Yves-Francois Blanchet, leader of the Bloc-Quebecois, said in a French statement on X that the English-only message is especially disheartening because one of the pilots killed was a "French-speaking Quebecer".

Blanchet called it a "sad and gross lack of respect towards the loved ones and family of the pilot".

Legault, the Quebec premier, told reporters that he believes Rousseau should resign if he is unable to speak French.

Rousseau lives in Montreal but is an anglophone. His uniligualism was the subject of criticism from some when he was appointed as CEO of Air Canada in 2021.

Shortly after his appointment, he was asked by a journalist why he has not learned French despite living in Quebec for more than a decade.

Rousseau responded: "If you look at my work schedule, you'd understand why" - a comment that garnered backlash from both Quebec and federal ministers at the time.

Rousseau later apologised and committed to improving his French.

The criticism over the condolence message is part of a broader conversation in Canada about the French language, as the proportion of Canadians who speak both official languages has been declining.

Air Canada began as a federal public corporation and has been private since 1988. It remains subject to Canada's Official Languages Act, however, and announcements on board planes are made in both English and French.

Investigators in New York are still working to determine what led to the fatal collision on Sunday.

National Transportation Safety Board Chair Jennifer Homendy said the inquiry would include interviews with the two air traffic controllers who were on duty.

Investigators on Tuesday released details from the final three minutes of cockpit voice recordings and tower communications, including that controllers had cleared both the plane and a fire truck to cross the runway.