The ban on nonessential international travel to and from England will stay until at least May 17, Prime Minister Boris Johnson said Monday, prolonging the pain for airlines, airports and holiday companies hit by the pandemic travel slump.

But would-be holidaymakers will be given clarity on making plans for the summer by April 12, when a review on how to restart travel safely will be published.

"The government will determine when international travel should resume, which will be no earlier than 17 May," it said.

Johnson told parliament that meant there was still time for Britons to plan summer holidays.

"I believe that setting a deadline of April 12 for the report... will give people time to make their plans for summer and if things go well... then I do believe there is every chance of an aviation recovery later this year," he said.

Airlines are counting on a summer recovery after close to a year with minimal revenues due to travel restrictions. If they cannot, analysts say most airlines will need to raise more funds to survive after burning through their cash reserves.

Responding to the government's plans, easyJet welcomed reassurances that travel would reopen, while British Airways said it was pleased the government had acknowledged it was critical to find a way to restart travel.

Shares in both companies closed up 7 percent, outperforming a 4 percent rise in Europe's travel and leisure sector.

But aviation consultant John Strickland said the timeline was negative for airlines, given certainty on travel was months away at a time when bookings would usually be flooding in.

"We're already two months into the year so we've lost two months already. On this news we're going to lose another two months," he said.

"A number of airlines are already projecting that at least the first half of summer is pretty well written off and projecting at best there might be some resurgence of traffic in the late summer."

The trade body for Britain's airports also said the May 17 date was a blow.

"As the worst-hit economic sector in 2020, this will ensure we will also be the worst-hit sector of 2021," Airport Operators Association Chief Executive Karen Dee said.

The April review will provide recommendations about when and how full international travel should resume, while managing the risks of new variants of coronavirus.

Much will depend on the spread of variants deemed "of concern," as well as vaccine rollouts at home and abroad.

Britain tightened its borders earlier in February, introducing additional COVID-19 testing ­requirements and hotel quarantines for arrivals from some countries over worries about new variants that might be more resistant to current vaccines.

Unwinding restrictions could involve making greater use of the test to release scheme, under which those arriving from abroad pay for a test to shorten a 10-day quarantine.

The government is also looking at a system of allowing vaccinated people to travel more freely abroad, it said.

But such a system would have to be fair and not unduly disadvantage those who have not been vaccinated, it said, warning it would take time to implement.