Each week, we answer frequently asked questions about life during the coronavirus crisis. If you have a question you'd like us to consider for a future post, email us at goatsandsoda@npr.org with the subject line: "Weekly Coronavirus Questions." See an archive of our FAQs here.I live in the U.S. and am considering a trip to another country. What do I need to know about international air travel at this stage of pandemic?First of all, you have plenty of company. International air travel is expected to surge this summer. Americans are thinking of European vacations again. "We've had people asking a lot about Europe," says Chicago-area travel adviser Kendra Thornton of Royal Travel & Tours. "Not necessarily booking but wanting to keep tabs on it."In addition, residents of the U.S. with family members in other countries are eager for a reunion after pandemic-enforced separations. People may be traveling abroad for work as well.They'll run into quite a range of travel restrictions and entry requirements.NPR correspondent Jason Beaubien was surprised to see his face on a giant screen in an airport in Sierra Leone, where thermal scanners take the temperature of everyone in the crowd simultaneously. Airport personnel takes aside anyone who registers a fever for evaluation.Travelers headed to Peru should pack a face shield. You have to wear it in crowded spacessuch as an airport.What's more, the protocols may change as new variants, such as the highly contagious Delta variant, spread and take hold in different countries.So if you're itching to travel abroad or have already booked a trip, you probably have a lot of questions. Here are some guidelines that might help you deal with the new rules of international flight:The Centers for Disease Control and Prevention says to get vaccinated before you go. Air travelers should be fully vaccinated regardless of the risk level in the country you're visiting, according to the health agency. There's still a lot of virus circulating.Keep track of the ever-changing guidelines and restrictions for your destination. You can check specific travel requirements through the U.S. State Department website or your destination's Office of Foreign Affairs or Ministry of Health.In addition, the CDC providesguidance on travel to other countries, which are ranked from "very high" risk of COVID-19 transmission to "low" (among them China, Iceland and Rwanda).Avoid countries in the "very high" category unless it is essential travel. There are 60 countries on this list, ranging from Argentina to Yemen.Some countries are closed to visitors but make exceptions. Belgium, Canada, the United Kingdom and Uruguay are a few examples. But some of these "no visitor" countries may make exceptions for the death or serious illness of a family member. If those are your circumstances, you may be able to visit. But the authorities might not/will not take your word for it. Expect to have to show proof of the reason for the visit, such as a death certificate or a doctor's note about a family member's illness. You can inquire about rules in your destination by contacting the American Embassy or Consulate there, or the country's embassy in the United States.And changes occur almost daily in this matter, so it's good to keep an eye on the State Department's or the country's official website for updates.Bring your vaccination card. Some countries want to see your vaccination card, so make sure your official CDC vaccination card is filled out with the date of your dose or doses (if you received a two-dose vaccine). It's a good idea to make a copy of the card or have a photo on your phone as backup, suggests Thornton, the travel adviser.Lost your card? Reach out to your vaccination provider or contact your state health department's immunization information system.You can also present the World Health Organization international certificate of vaccination, also known as a yellow card. You can ask your vaccine provider to add your COVID-19 vaccination info if you already have a card. Or if you need one, you can purchase it through the U.S. Government Bookstore, which tells NPR it has seen a 55% increase in sales in the last six months. Cards are on back order but should be available by the end of June. Or you can purchase one from the WHO, which means waiting at least a week for shipment from Switzerland.What about vaccine apps? Vaccine apps that show your record could be accepted as well, but there's no guarantee that border control will accept these as proof, so bringing a paper record is a good idea.Citizens of the European Union will soon have a Digital COVID Certificate system that provides a scannable QR code to verify vaccination status and coronavirus test results. This should smooth travel between member states but won't help a vaccinated tourist from outside the EU.Airlines are trying to help their customers meet the vaccination and testing requirements of various countries by developing their own apps. The International Air Transport Association has rolled out its own IATA Travel Pass, which many major airlines around the world will use.But officials say calling it a vaccine passport, as many people are, is a bit of a misnomer."It's more of a digital credential associated with your vaccination or testing profile," the IATA's Nick Careen says. "So the consumer can use that to help them through their passenger journey."British Airways, Japan Airlines, Qatar Airways and Emirates are among the global airlines running trials of IATA's travel pass app, which is expected to go live soon.Other airlines, including American, will be using an app called VeriFly.American's Preston Peterson told NPR that "because the requirements for entry differ by almost every single country and, in some cases, by the region within a country," the app will give the customer "the peace of mind to know that they comply with those different regulations.""A customer can submit their documentation, have it verified and then they receive a green check mark, or effectively, an OK to travel status, that we as the airline trust, the customer can trust and then they know they're ready to go," Peterson says, adding that the app will update in real time as entry requirements for various destinations change.But even proof of vaccination may not be sufficient to ease your entry. Some countries don't care if you have a vaccine card, as they can be easily faked or forged, or a digital vaccine pass on an app. They'll still insist on a PCR test to determine if you're infected several days before flying into and out of their airports. Most countries are asking airline personnel to verify the test. A positive result means the trip is off. That's the case in Egypt, some European countries and Israel. And you can't leave Ben Gurion Airport in Tel Aviv, Israel, after arrival in the country without taking a coronavirus test; airport personnel usher everyone to the clinic tent right after baggage claim.Even if you're vaccinated and tested negative for the coronavirus, you may have to quarantine. Samoa, for example, requires a minimum 21-day quarantine for all incoming passengers.Keep up on testing requirements before your departure. They definitely change. Because of the high rate of cases, Namibia on June 1 changed its visitor entry rules from a simple self-test for the coronavirus to a typically more expensive laboratory test conducted before leaving your home country and not older than seven days before your arrival.The State Department site dates its updates so you can see when a change was made, and it also provides links to specific country guidelines provided by U.S. consulates and embassies.Check the latest requirements three days before your flight just to make sure. Some airports, such as Chicago's O'Hare Internationaland Los Angeles International, offer on-site coronavirus tests, but these can be pricier options than you might find elsewhere. And airport testing sites might have limited hours, so check before you head to the airport.Get alerted. It's a good idea to sign up for noticeson international travel from the State Department, says Zane Kerby, president of the American Society of Travel Advisors. In Portugal, for example, increased cases of the COVID-19 variant known as Delta, identified as likely more transmissible and causing more severe disease, has put the country at a higher risk level.Bring proof of health insurance. Even if you're a veteran traveler who knows that your insurance carrier covers you overseas, be sure to check on COVID-19 coverage before you leave. Some countries, such as Argentina, require that you have a notice from your health insurer that specifically mentions COVID-19 coverage as proof that you are covered for the virus. Cambodia requires all foreigners to purchase insurance from the government on arrival: $90 for 20 days of coverage. Also check to see if your policy covers medical evacuation insurance, or consider buying a separate policy if not. Travel specialists say it's a wise investment during a pandemic.The CDC offers great background information on health insurance and foreign travel on its site. If you buy a supplemental plan, the State Department site recommends looking for one that will pay for care directly rather than reimburse you so out-of-pocket expenses are limited.Brush up on testing requirements. All air passengers coming to the United States — residents who have traveled abroad and visitors as well — are required to have a negative coronavirus viral test no more than three days before travel or documentation of recovery from COVID-19 in the past three months before they will be allowed to board a flight to the United States.That test can be either a so-called molecular test done at a laboratory that can detect specific genetic material from the virus and is the most precise test, or an antigen test — which can be done as a self-test — which detects proteins on the surface of the virus if you were infected.Embassy and consular notes on the State Department's travel website offer detailed information on locations for a molecular test in each country if available. In some countries. the test is free. Or it could cost up to $200. Check the State Department travel site, which offers frequently updated, detailed testing requirements and resources for many countries.Self-tests are a limited option. Right now, only two airlines are making self-tests easily available United and American – and you need to be able to perform the self-test while conducting a telehealth visit with a designated clinic. For more information, contact United or American if you will be returning home on either carrier oreMed.com, a telehealth company handling the testing to see if you qualify for the self-test, even if you're on another carrier.If you're not vaccinated, though, you may want to choose a lab test rather than the self-test for re-entry, "especially if you're returning from a country experiencing high rates of COVID-19," says Matthew Binnicker, vice chair of practice in the Department of Laboratory Medicine and Pathology at the Mayo Clinic. That's because the lab test can be more accurate than the self-test, according to guidelines published by the Infectious Diseases Society of America.Don't forget your mask. While some jurisdictions around the world are beginning to loosen COVID-19 restrictions, the Transportation Security Administration in late April extended its mask requirement to Sept. 13 (and could extend it further) for U.S. airports and on board U.S. airlines. Many foreign carriers have the same rule.Fran Kritz is a health policy reporter based in Washington, D.C., who has contributed to The Washington Post and Kaiser Health News. Find her on Twitter: @fkritz Copyright 2021 NPR. To see more, visit https://www.npr.org.