The operation was a challenge for airports in Atlantic Canada. Transport Canada asked Nav Canada to instruct flights coming from Europe to avoid Macdonald-Cartier International Airport in Ottawa, as well as Lester B. Pearson International Airport in Toronto and Dorval International Airport in Montreal as a security measure, since they are among the major—and therefore busiest—airports in Central Canada. The majority of incoming flights from Europe were received by Atlantic airports, though some diverted flights did land at Dorval and Pearson.