The UK government announced a traffic-light system to allow international travel to resume safely.
But ministers would not say whether foreign travel would resume on May 17 as scheduled in the government’s road map out of lockdown, with another announcement expected before then.
A traffic-light system will be used to categorise countries based on coronavirus risk, while travellers will need to pay for tests when departing and returning to the UK.
Transport Secretary Grant Shapps said for the first time in months people could consider taking trips abroad.
"I think everybody doing it understands there are risks with coronavirus," he told Sky News on Friday.
"For the first time, people can start to think about visiting loved ones abroad, or perhaps a summer holiday, but we're doing it very, very cautiously because we don't want to see any return of coronavirus in this country.”
He said people would probably plan to travel to destinations on the green list – for which two Covid-19 tests are required for travel – and details on which countries make up the list will be finalised in early May.
Travellers coming from amber list countries will be required to take two tests, as well as quarantine at home for 10 days.
Most would-be travellers are not expected to book trips to red-list countries because of the requirement to enter hotel quarantine on return to Britain.
Although much of Europe is suffering a third wave of infections, the prospect of quarantine-free travel to popular holiday destinations, such as Spain, looks likely to resume in time for the peak summer season.
A review of the plan is scheduled for June 28 when rules on testing and quarantine could be relaxed for amber countries.
The government's travel task force said work was going on to develop a certification system, sometimes called vaccine passports, for inbound and outbound trips.
The plans fell short of the tourism industry’s hopes, with a row breaking out over the cost of testing for returning travellers.
Airlines criticised the "prohibitive cost" of tests and said the price put international travel beyond the means of many people.
Post-arrival tests are of the PCR type, which cost about £120 ($164) per person.
Tim Alderslade, the chief executive of Airlines UK, which represents operators such as British Airways and easyJet, said the announcement did “not represent a reopening of travel as promised by ministers”.
“It is a further setback for an industry on its knees and the UK’s wider economic recovery,” he said.
EasyJet, Britain's biggest airline by passenger numbers, said the government should reassess its PCR test requirement plan.
"This risks reversing the clock and making flying only for the wealthy," easyJet chief executive Johan Lundgren said.
Paul Charles, director of The PC Agency travel consultancy, said cheaper lateral flow tests should be used for green-list countries.
“This would bring down costs substantially and then restore confidence to book. At present, there are still too many layers of complexity to travel for those simply wanting a well-earned break or family visit in a safe country,” he tweeted.
Shai Weiss, Virgin Atlantic chief executive, said the industry needed weeks of notice to resume significant international travel.
"You don't just ramp up an airline in a few days, so a bit of clarity on which countries will be on the green list allows us – and consumers and businesses – to book with confidence this summer," he told BBC Radio 4's Today programme.
The government said it was working with the travel industry and with private Covid-19 test providers to cut the cost of travel.
"This could include cheaper tests being used when holidaymakers return home, as well as whether the government would be able to provide pre-departure tests," the travel task force said.
Under the traffic-light system, restrictions such as hotel quarantine, home quarantine and compulsory Covid tests will apply differently depending on the category of country a passenger arrives from.
Factors include the percentage of population vaccinated, the rate of infection, the prevalence of variants of concern and the country's access to reliable genomic sequencing.
There will be a green watchlist to identify countries most at risk of moving from green to amber status, although the government said it would not hesitate to change a country's category should data show increasing risk.
The task force indicated that a digital travel certification system would be part of the plan but gave few details beyond saying that Britain wanted to play a leading role in developing standards in this area.
How does the traffic-light system work?
Green Passengers will not need to quarantine on return, but must take a pre-departure test, as well as a PCR test on return to the UK
Amber Travellers will need to quarantine for 10 days, as well as taking a pre-departure test and two PCR tests
Red Passengers will have to pay for a 10-day stay in a managed quarantine hotel, as well as a pre-departure test and two PCR tests