Three U.S. airlines have given up on Cuba since March, but JetBlue Airways still sees opportunity.

The airline on Thursday asked the U.S. Department of Transportation to let it fly seven new weekly flights to Havana — six from Fort Lauderdale and one from Boston. JetBlue already flies 13 times per week from Fort Lauderdale to Havana, but, in the initial awards, it did not win the rights for a Boston flight. Under an agreement between the United States and Cuba, U.S. airlines may fly only 20 daily flights to Havana, and when the frequencies were made available, airlines applied for far more flights than were available.

But much changed since mid-2016, when the U.S. government selected which airlines could fly what routes. In the past six months, several airlines have reported Cuba flights were less profitable than expected, and some have decided they no longer want to fly them. Spirit Airlines will pull out of Cuba on May 31, while Frontier will drop its lone flight from Miami to Havana on June 4. Small regional airline Silver Airways is also dropping all nine of its routes to the island as of Saturday.

American Airlines has also cut some of its Cuba service, though it still has a strong schedule, especially from Miami.

“Cuba continues to be a flop for all involved,” Hunter Keay, an analyst with Wolfe Research, wrote last month.

JetBlue has had its own challenges, and in February said it would fly smaller jets to Cuba. Beginning on May 2, JetBlue is subbing a 150-seat Airbus A320 for a 200-seat A321 on flights from New York, Fort Lauderdale and Orlando. Also, from Fort Lauderdale to Santa Clara, Camaguey, and Holguin, the airline will use a 100-seat Embraer E190 rather than an A321.

In an email, JetBlue spokesman Philip Stewart acknowledged the carrier has cut capacity to Cuba, but said asking for the new frequencies is more of a long-term play. He noted that JetBlue flew charter flights to Cuba before it launched scheduled service, and suggested the airline may know the market better than some of its competitors.

“We hold an optimistic long-term view as visitor levels grow at a record pace,” he said. “JetBlue launched commercial service with years of operational expertise in this unique market. As less experienced airlines are eliminating routes, we have optimized our schedule and operation to balance long-term opportunities with the current developments in this important market. We are assigning smaller aircraft to these routes and will continue to adjust as needed to ensure sustainable performance.”

As for Boston, this is not the first time JetBlue has sought the right to fly the route. After losing in the initial awards, the airline tried to get the government to take away a Cuba flight from Alaska Airlines and give it to JetBlue.

It happened after Alaska asked to delay the start date of its Los Angeles-Havana flight from Nov. 29 to Jan. 5. JetBlue objected, saying if Alaska was not ready, the award should instead go to JetBlue, which would use it for a Boston flight. The Department of Transportation rejected the claim, and Alaska is now flying to Havana.

“We have always planned to serve Cuba from Boston, and our application for a once-weekly flight reflects demand where there is no competitive service,” Stewart said.

JetBlue wants to add the extra flights on Nov. 1.

Photo Credit: Ground staff cheer one of JetBlue's first flights to Cuba in August 2016. The airline wants to add more flights to Havana. JetBlue Airways