New restrictions on flights from the Caribbean and Mexico announced Friday are likely to trigger bankruptcies in Canada's airline sector and force permanent closures for airports and travel agencies, aviation experts say. "Today's announcement really was the nail in the coffin for the airline and tourism business," said Robert Kokonis, founder and managing director of aviation consulting firm AirTrav Inc. "We're going to see bankruptcy filings, you might even see a few outright failures." John Gradek, a lecturer at McGill University and the head of its Global Aviation Leadership Program...