Southwest is one of six US airlines which have been licensed to operate up to 90 round-trip flights per day to Cuba, potentially opening up a new era for mass tourism. (Karen Bleier/AFP/Getty Images)

Eight U.S. airlines will be awarded 20 direct daily flights between U.S. cities and Havana, with service to begin this fall, the Transportation Department announced Thursday.

The airlines, whose selections won’t be finalized until the end of this month, will fly primarily from Florida — including six daily flights from Miami — although six other cities around the country are also included. A bid by United Airlines to operate direct flights from Washington was not approved.

The Transportation Department announcement said the selections were made to allocate nonstop Havana service to “areas of substantial Cuban-American population, as well as to important aviation hub cities.”

The announcement is one of the last steps toward putting into effect a commercial aviation agreement signed by the two countries in February as part of normalizing their relations. Separate awards announced last month authorized a smaller schedule of U.S. flights to other Cuban cities.

An American Airlines airplane prepares to land at Jose Marti International Airport in Havana last September. (Carlos Garcia Rawlins/Reuters)

Although authorized charter flights began service to Cuba decades ago, regularly scheduled service has been prohibited since the early 1960s as part of U.S. economic sanctions against Cuba.

The normalization agreement also allows for Cuban airlines to fly to the United States, but Cuba has made no application to the Transportation Department for its national carrier, Cubana de Aviacion, to begin service. The Cuban government has put the issue “on hold” because of concerns that the government-owned planes could be seized to settle financial judgments against Cuba, according to John Kavulich of the New York-based U.S.-Cuba Trade and Economic Council.

U.S. courts have awarded damages totaling up to $2 billion in legal cases, most of them involving the 1996 Cuban shoot-down of a plane operated by the ­Miami-based exile group Brothers to the Rescue.

Separately, the U.S. Foreign Claims Settlement Commission has certified 5,913 property claims against Cuba for seizures following the 1959 revolution. Settlement of those claims, also totaling close to $2 billion, is part of ongoing U.S.-Cuba normalization. An unknown number of claimants have won court judgments outside the official settlement process.

Tourist travel to the island is still illegal under the remaining U.S. trade embargo, which only Congress can remove. But the Obama administration has greatly loosened restrictions on who can travel there, including approval of individual visits for self-declared “people-to-people” exchanges.

In the year following the announcement of normalization made by the two governments in December 2014, nearly 150,000 Americans — not including individuals of Cuban descent — visited Cuba out of more than 3 million visitors, according to Cuban statistics.

Figures for the first six months of 2016, visits are on track to total more than 300,000 this year, with an economic impact Kavulich estimated at about $630 million.

But he predicted a “massive choke point” as travel increases to Cuba, which operates only 64,000 hotel rooms. While the use of some U.S. credit cards and cellphone connections has been approved, the transactions and calls are often unworkable. Internet connections remain spotty.

U.S. carriers, however, clearly see Cuba as a potentially lucrative new market, and the routes tentatively awarded Thursday followed heated competition. Twelve carriers applied to carry passengers and cargo; the sharpest contest was between JetBlue and American, which vie to dominate U.S. travel to the Caribbean.

Carriers and tentatively awarded Havana routes included: Alaska Airlines, once daily from Los Angeles; American Airlines, four times daily from Miami and once daily from Charlotte; Delta Airlines, once daily from New York (JFK), Atlanta and Miami; and Frontier Airlines, once daily from Miami.

Others were JetBlue Airlines, twice daily from Fort Lauderdale (but once on Saturdays), and once daily from New York (JFK) and Orlando; Southwest Airlines, twice daily from Fort Lauderdale and once from Tampa; Spirit Airlines, twice daily from Fort Lauderdale; and United Airlines, once daily from Newark and once weekly (Saturdays) from Houston.

This story has been updated to note that 300,000 vists by Americans to Cuba are expected this year, not that there have already been 300,000 visits in the first six months of 2016.