The world awaits pandemic weary travelers, who are vaccinated against COVID-19 and ready to hit the road. United Airlines (UAL) announced Monday, in its Q1 earnings report, that it will begin flying this July to Iceland, Greece, and Croatia "moving to capitalize on emerging pent-up demand for travel to countries where vaccinated travelers are welcome."

The key, of course, is for a passenger to prove they have been vaccinated. Countries like Israel and China are already using digital certificates to allow citizens to travel while New York state is using The Excelsior Pass.

These digital documents allow people to "present digital proof of COVID-19 vaccination or negative test results." They are often called vaccine passports but Delta Air Lines (DAL) CEO Ed Bastian told Yahoo Finance Live, "We don't call it a vaccine passport. It carries too many connotations."

Vaccine passports have been a political hot potato since the Biden administration proposed in January to merge coronavirus testing documents with vaccination records.

Bastian said Delta, like United is, "more focused on a credential, travel credential, if you will, to indicate that you've been vaccinated and or tested based on the regulatory requirements."

Bastian predicts international passengers will have to prove some form of immunity from the coronavirus which causes COVID-19. "Either a vaccination or a test," he said. "We're working with a number of technology providers to be able to facilitate that in an open source way."

Vaccine passports 'a DMV on steroids'

"The challenge with vaccine passports is that it’s one more document that airlines will need to deal with," according to airline consultant Mike Boyd, president of Boyd Group International.

He said it is unlikely nations worldwide will ever agree on a vaccine passport standard. "Airlines would rather not deal with this, but they need to express their points of view very carefully," Boyd warned.

Requiring a vaccine passport, Boyd said, and then setting up a global protocol to enforce it, would be a bureaucratic process that, "could resemble a DMV [Department of Motor Vehicles] on steroids."

Just don't call it a passport

The World Economic Forum Common Trust Network, a coalition of governments and global airlines, is attempting to avoid the bureaucratic nightmare. It created the CommonPass app to simplify COVID-19 regulatory compliance worldwide.

The Common Trust Network describes the app as "a trusted, globally-interoperable platform for people to document their COVID-19 status (health declarations/PCR tests/vaccinations) to satisfy country entry requirements, while protecting their health data privacy." But the coalition does not call it a passport.