As the International Air Transport Association continues to trial its digital pass, in a bid to enable safe travel amid the Covid-19 pandemic, Dubai Airports chief executive Paul Griffiths has said wider implementation of the system is "inevitable".
Speaking to the BBC, Griffiths said: "I don't think there is an alternative."
He said: "I think the problem is not the vaccine passport and its discrimination. It's the need to roll things out and have a proper globally equitable vaccine programme."
Systems such as the Iata Travel Pass have sparked concern over whether they ultimately discriminate against those who cannot get vaccinated.
In April, the UK's Equality and Human Rights Commission said that while vaccination certificates could help to ease restrictions "in principle", they could also create a "two-tier society whereby only certain groups are able to fully enjoy their rights".
How does the Iata Travel Pass work?
The Iata Travel Pass is a free mobile app that allows travellers to register their personal details, find out coronavirus-related testing requirements for their destination and share pre-departure Covid-19 test results with airlines before flying.
In the future, there are also plans for the app to house vaccination records, to help facilitate easier travel between countries demanding people show proof of having been inoculated against coronavirus.
The app is one of several digital initiatives currently in trial phases.
What documents do you need to use the Iata Travel Pass?
To use the digital pass, passengers will need a biometric passport.
As the app is currently in trial stages, travellers will only be able to use it if they are flying with an airline and on a route where it is being tested.
For travellers flying Etihad, it will be trialled on flights between Abu Dhabi and Chicago, New York, Washington and Toronto until Monday, May 31.
Emirates is also trialling the app on select routes, including to Barcelona and from London, with more destinations in the pipeline.
Other airlines trialling the pass include Singapore Airlines, Qantas, Gulf Air, Virgin Atlantic, Iberia and Qatar Airways.