OTTAWA/MONTREAL—Struggling tour operator Air Transat is in talks with the federal government on aid but may not reach a deal by an April debt deadline, a source close to the situation said, putting pressure on Quebec to ride to the rescue of another troubled aerospace brand in the province. Air Canada dropped its merger plans with Transat on Friday, saying European regulators had signalled it was unlikely to pass antitrust concerns. Canada’s largest carrier first bid for Transat in 2019 and discounted its offer last year as the pandemic decimated the travel and tourism sector. Airlines have been in talks with Ottawa since last year about a possible aid package. Transat’s aborted deal adds fresh urgency to the talks, given the jobs at risk if the carrier fails and the political importance of Quebec ahead of an expected federal election this year. Transat, which last month suspended flights until June …