The hurricanes will cost Southwest Airlines $100 million in revenue.
The airline says it canceled 5,000 flights through Wednesday because of Hurricanes Harvey, Irma and Maria. Southwest still hasn't restored full service to Puerto Rico and other parts of the Caribbean.
American, United, Delta and JetBlue have all canceled many flights, too, but those airlines haven't said yet what it will cost them.
The main airport in Puerto Rico still has only limited commercial passenger service. Equipment was damaged by Maria, generators are supplying the only power, and relief flights full of emergency supplies are using the runways. Thousands of passengers are packed into a sweltering terminal without air conditioning hoping to get a flight out.
But Puerto Rico is not a major hub. Houston and Miami are, and their airports were closed for days because of Harvey and Irma.
American said earlier this month that it canceled about 5,000 flights because Florida airports were closed for several days during Irma. American didn't estimate how much revenue it would lose, but it said the storms and higher fuel costs would hurt profits.