As we enter the first summer of this new era of pandemics, a tenuous easing of travel restrictions has begun. This month, the countries of the European Union will reopen their internal borders, and they plan to allow travel from outside the block some time in July. Singapore and China have begun permitting essential travel between them, but only for passengers who test negative for the coronavirus, use a contact-tracing app, and don’t deviate from their itinerary. Iceland will allow tourists, but it plans to test them for the virus at the airport.

Grounded for many months, airlines are beefing up their summer schedules—though the number of flights will be a fraction of their pre-pandemic frequency. Airports are still mostly ghost towns (some have even been taken over by wildlife), and international long-distance travel is all but dead. Around the globe, the collapse of the tourist economy has bankrupted hotels, restaurants, bus operators, and car rental agencies—and thrown an estimated 100 million people out of work.

With uncertainty and fear hanging over traveling, no one knows how […]