FRANKFURT, Germany — A nonprofit foundation is testing a smartphone app that could make it easier for international airline passengers to securely show they've complied with COVID-19 testing requirements. It's an attempt to help get people back to flying  after the pandemic sent global air travel down by 92%.

The Switzerland-based Commons Project Foundation was conducting a test Wednesday of its CommonPass digital health pass on United Airlines Flight 15 from London's Heathrow to Newark Liberty International Airport, using volunteers carrying the app on their smartphones. Officials from the U.S. Centers for Disease Control and Prevention and Customs and Border Protection were observing the test.

The system looks forward to the day when travel may be determined not only by testing but by the need to show vaccination records. The World Health Organization says vaccines may start becoming available by mid-2021, though efficacy and availability to broad parts of the global population remain large question marks.

Foundation CEO Paul Meyer said the pass is "intended to give people the ability to travel again by documenting that they meet the requirements of the places they want to go… This is a way to get things moving again."

The problem: the pandemic has led to a patchwork of travel bans, quarantines and testing requirements, with each country imposing its own rules. Testing is seen by airlines as a way to reassure passengers and allow people to skip quarantines, but there's no common approach. When it comes to testing, passengers may present paper documents in different languages and from labs unknown to authorities in a given country. 

The CommonPass project, carried out in cooperation with the Switzerland-based World Economic Forum, aims to establish standard ways to verify lab results and, later, vaccination records, even if governments continue to set different health criteria.

Scientists warn there are concerns about the accuracy of some rapid tests. People can be infectious for several days before they show symptoms, and these people may also test negative. The project's chief medical officer, Dr. Brad Perkins, said that two tests during long-distance travel — one 72 hours before departure and one on arrival — would cover the incubation period. Testing technology may continue to evolve during the pandemic.

Passengers can use the app to find participating labs and testing sites, retrieve lab results and complete health attestations. The app and its associated data platform can confirm their results are in line with the destination's requirements and generates a QR code that authorities can use to confirm compliance.

The foundation says this system protects privacy because people do not need to share their health information, only compliance or noncompliance. Additionally, CommonPass could be deployed by countries without waiting for a broader international agreement.

 The system is intended to be adaptable whenever requirements change. 

Meyer said that capability would be important after the arrival of vaccines, which may differ as to number of doses and length of time they're effective.

"Let's put the foundational infrastructure in place that gives countries the flexibility to adapt those rules over time, and then allows travelers to effectively bring their information with them and demonstrate that they satisfied the rules that are in place at the time they want to travel," he said.