The window to find dirt-cheap fares to Europe is closing.

Monday was Monday when the Biden administration announced that in November the U.S. would allow vaccinations from 33 foreign countries. This is in response to the earlier rules in the pandemic.

This is great news for airlines looking to increase revenue following a period of low demand on routes once very popular prior to the Covid-19 epidemic. The United States has not reciprocated the hospitality of many EU countries that have opened their doors to U.S. visitors for several months.

Conor Cunningham of MKM Partners wrote in a research note that investors, “In the past as restrictions have been relaxed, there has been a rise in travel bookings. We expect a similar response here.”

As trans-Atlantic travel increases, bargain hunters who want to grab cheap tickets may be disappointed.

Hopper, an airfare-tracking company, stated that round-trips to Europe from the U.S. now cost about $565. That’s a record level in just five years.

The European Union’s recommendation that all member countries remove travel restrictions from the U.S. had resulted in fare drops of 15%. However, the advisory was not binding and U.S. tourists can still travel to many other countries as long as they satisfy certain requirements, such proof of Covid-19 vaccination, or even a negative Covid testing.

Hopper’s economist Adit Damodaran said that he expected airfares to increase from Europe to America due to loosening travel restrictions. He also expects the U.S. will be more open to European travelers as more people realize that the EU advisory was a “soft advisory.”

Airlines didn’t immediately say whether they would add flights following the loosened U.S. travel rules, but carriers pounced with added service to destinations like Iceland, Croatia and Greece when those countries started allowing U.S. visitors in earlier this year.