The United States and Cuba are close to a deal on restoring regularly scheduled commercial flights. The diplomatic advance would help open the way for US airlines to begin flying to Cuba within months. Officials on both sides said they had reached an understanding on key points and hoped to reach a formal deal within hours or days. Right now, American and Cuban travelers must fly on charter flights that are expensive and difficult to book, forcing travelers to buy paper tickets in Cuba or email documents and payment information back and forth with an agent in the US. Those flying often must arrive at the airport four hours in advance and pay high prices for baggage in excess of strict weight limits.

U.S. officials and aviation executives have speculated that Cuba could allow more than a dozen flights to and from the US a day. It’s unclear if those flights would completely replace charters, but they appear certain to create a surge in travel that would place heavy strain on Cuba’s already overstrained tourist infrastructure. Hotels and private hostels are booked for months.

Since the announcement last year that the U.S. would establish diplomatic relations and expand trade and tourism with Cuba, major U.S. airlines, including American, Delta, United, JetBlue and Southwest, have expressed interest in establishing regular flights from the U.S. to the island. Cuba and the U.S. announced last week direct mail service would restart after a 52-year interruption.

The governments had been speaking about restoring a postal link since President Barack Obama entered office, but those talks stalled when Cuba imprisoned U.S. contractor Alan Gross. He was freed in a prisoner exchange that sparked last year’s declaration of detente. The U.S. and Cuba re-opened embassies in each other’s capitals this summer.

Thursday (December 17′ 2015) marks the one-year anniversary of the announcement by Presidents Obama and Raul Castro that they were ending a half-century of U.S.-Cuban enmity.