Passengers on United Airlines and Cathay Pacific are trying out an app called the CommonPass.

The phone software is a digital health pass which can hold a certified COVID-19 test status or show someone has been vaccinated in future in a way designed to satisfy various governments' different regulations.

It has been launched by non-profit trust Commons Project Foundation, part of the World Economic Forum, in the hope of it will end the days of flyers producing bits of paper, often in different languages.

The tech is very much at the trial stage using volunteers on flights between London, New York, Hong Kong and Singapore under government observation.

But it is seen as a longer-term measure to allow air travel to return to something like pre-coronavirus levels. 

However, it is reliant on Governments around the world accepting test results from 'certified' laboratories in other countries and allowing those with negative results to enter freely on their say-so.