Air France, which operates 121 flights weekly between the United States, said on Thursday that it would fly only a handful of routes from Friday until March 28 and was working on a plan to operate beyond that. The French government said it was ready to provide state aid — an extraordinary step normally forbidden under European Union rules.

“The impact will multiply very rapidly in the hours and days to come,” said Roland Héguy, president of the Umih, the French trade association of hotels and restaurants. “Many countries will be hit,” he said, adding that 95 percent of hotels, cafes and restaurants in France were already suffering revenue declines of up to 40 percent because of the coronavirus.

Given how much economic damage has already been done in Europe from the epidemic, some economists said the travel ban, while shocking, would not meaningfully deepen the downturn — and might even help hasten a recovery.

“Considering all the other restrictions on movement already in place in Europe, in and of itself the ban is not a huge economic event,” said Holger Schmieding, chief economist at Berenberg Bank. “You could even argue that it is a blessing in disguise if it has the effect of slowing the spread in the United States,” he said.

Because the epidemic is a medical emergency, he added, the most important thing governments can do to to ensure economic recovery is to prevent the virus from spreading more widely, even if it inflicts financial pain on companies.

“At the moment, significant short-term economic costs should be incurred if it helps with the medical emergency,” he said. “If it slows the spread of the epidemic to give us enough time to cope, that would be very valuable.”

Nonetheless, the abrupt travel ban threatened a further blow to tourism-dependent industries on both sides of the Atlantic, and added to the problems of world leaders trying to preserve jobs in the face of the relentless coronavirus outbreak.