The International Air Transport Association (IATA) says it expects its digital Covid Travel Pass will be ready "within weeks".
The pass is an app that verifies a passenger has had the Covid-19 tests or vaccines required to enter a country.
It also verifies they were administered by an approved authority.
The industry body sees the pass as essential for reopening air travel, as many countries still have strict restrictions or quarantines in place.
"The key issue is one of confidence. Passengers need to be confident that the testing they've taken is accurate and will allow them to enter the country." said Vinoop Goel, IATA’s regional director of airports and external relations.
"And then governments need to have the confidence that the tests that the passengers claim to have is one which is accurate and meets their own conditions."
IATA said the Travel Pass is designed in a "modular" way, so that it can work with other digital solutions that are being trialled around the world.
It will be available on iOS and Android platforms, and is expected to be free to passengers.
Singapore Airlines was the first airline to start trials of the travel pass in December.
Etihad, Emirates, Qatar Airways, Air New Zealand are among the other airlines currently conducting trials, and IATA says it is discussing the pass with most airlines throughout the Asia Pacific region.
"We are currently working with a number of airlines worldwide and learning from these pilots. And the plan is to go live in March," Mr Goel said.
"So basically we expect to have a fully functional working system over the next few weeks."
Paper versus app
The closest paper equivalent to the app is the Yellow Card, a World Health Organization document which confirms passengers have been vaccinated.
It is often used to prove that passengers have had yellow fever vaccinations required to enter some countries.
IATA says the risk of fraud with paper documents is too great.
Europol recently revealed that a forgery ring in France had been selling negative test results to passengers at Charles de Gaulle Airport and fraudsters had also been apprehended in the UK for selling forged results.
Malaysian police also reportedly recently arrested six Pakistani men suspected of forging negative results.
"This issue has come to the forefront, because there is the risk of fraud with paper certificates," said Mr Goel.
However, the insistence by some governments on paper documentation has proved an obstacle to the rollout of the IATA app.
"We do have a case in the Republic of Korea that does require a paper certificate, so we are working with the government there to ensure they will allow digital certificates to be accepted," Mr Goel said.
Essential for quarantine free travel
The airline industry is pinning its hopes on quarantine-free travel reopening this year, but expects progress to be slow, even with the app.
Covid has been disastrous for the airline industry, according to IATA’s figures, with demand plummeting nearly 70% in 2020 compared to 2019.
The industry is hoping for a recovery in 2021, but it’s unlikely that the vaccine rollout will solve the problem immediately, which is part of the reason IATA thinks the Travel Pass is needed.
"It will take too long. It will take at a minimum between 12 and 24 months. And it’s very dependent on the availability of vaccine globally," said Conrad Clifford, the body's regional vice-president for the Asia Pacific region.
"So we see a combination of testing and vaccination as being the long term solution to reopening borders," he said.