Preflight coronavirus testing is becoming increasingly popular at many U.S. airports as airlines attempt to lure passengers back on board during the pandemic. It is a trend that is growing globally that could help restore an industry hit hard by COVID-19.

According to The Washington Post, more than 100 countries now require documentation of negative results to allow visitors to enter. This might also eliminate the necessity to quarantine. International airports were the first to implement preflight tests for coronavirus but now airlines and airports in the U.S are jumping on the bandwagon.

Airports in Connecticut, Florida, New York, and San Francisco have offered the option as domestic air travel plummeted 64% during the pandemic compared to last year. Industry experts say, in lieu of a vaccine, testing is a necessary step to get people flying again, according to the Post.

Even though the Centers for Disease Control and Prevention strongly discourages any form of travel during the pandemic, testing could provide another layer of protection, along with wearing masks and observing social distancing.

It could also help contain the virus. Abraar Karan, a global health physician and resident at the Brigham and Women's Hospital, said testing can not only reduce the risk of spreading the virus on board planes but could also catch infected people leaving areas of high rates of transmission and slow it down. But he cautions, false positives can stop a healthy person from flying and a single test might not detect those in the earliest stage of illness.

"Testing is not a free pass," he said, adding quarantining is still the best way to isolate infectious travelers.

Florida's Tampa International was the first airport in the U.S. to offer both PCR tests and rapid antigen tests to all passengers during the month of October as part of a pilot program. Over 3,000 passengers were tested during that period.

"We're going to build confidence on the part of the traveling public, by giving them an opportunity to have a test done right here at the airport before they get on a flight," said Joe Lopano, CEO at Tampa International, at the time.

"Testing is the key to getting people back to travel," he said, according to CNN Travel.

Other airlines followed suit and reported an uptick in both bookings and volunteer testing from passengers – a win-win situation.

According to the Post, Sharon Pinkerton, senior vice-president of legislative and regulatory policy at the major industry trade group, Airlines for America, said early data shows preflight testing is effective in keeping passengers safe and giving airline travel a much-needed boost.

"In other words, it can help fuel economic recovery," she said.