LONDON (Reuters) – British Airways and Virgin Atlantic expect international travel from Britain to resume on May 17 despite the government warning it is too soon to say whether holidays can go ahead this year.

The UK government has said it will provide more details on restarting foreign travel this week after holidays were banned in the latest COVID-19 lockdown. But rising infection rates in Europe have threatened the hoped-for recovery.

Prime Minister Boris Johnson said on Monday he did not underestimate the challenge ahead.

The airline industry believes, however, that come mid-May more vaccines will have been rolled out in key destinations, bringing infection levels under control, while a UK traffic light system – tailoring rules to the risks in each country – should prevent coronavirus variants from being imported.

“We see nothing in the data that suggests that we shouldn’t be opening up travel on the 17th of May.” British Airways (BA) CEO Sean Doyle told a media briefing on Tuesday, referring to the government’s original plan for when travel might resume.

Speaking alongside Doyle, Virgin Atlantic CEO Shai Weiss said the United States should be on Britain’s “green” list of countries qualifying for relatively restriction-free travel.

BA and Virgin are rivals on trans-Atlantic routes.

Doyle was also optimistic the green list would have expanded by the summer as vaccination campaigns ramp up, particularly in continental Europe.

The government has advised Britons not to book foreign holidays, but after a year of minimal revenues due to the pandemic, airlines are desperate for an end to restrictions.

Without a significant resumption of travel this summer, most will need to raise new funds to help ensure their survival. They have taken on new debt to make it this far.

Both airline bosses declined to say how they would fine-tune their route maps to reflect likely green-list countries, which could include Israel, Portugal and the United Arab Emirates.

Doyle said BA was waiting for government recommendations expected later this week to plan its summer.

The bosses said they would need to know which countries were likely to be on which list and have enough detail to plan for May 17 and beyond, as bringing staff back from furlough, getting planes ready and opening terminals would take weeks.

The executives, and Heathrow airport CEO John Holland-Kaye who also spoke at the briefing, urged the government to approve the use of digital travel passes, which would include test and vaccine certificates. The industry has said checks on paper certificates would cause delays.

“We need to standardise and simplify and automate as much as possible,” said Holland-Kaye.