Travel companies are enjoying sales boom after the UK government lifted travel restrictions to a handful of countries as part of its easing of coronavirus lockdown measures.
Travel agents welcomed an increase in bookings following the announcement, but the boost still comes against a background of a ravaged industry.
Twelve countries are on the green list for relatively hassle-free travel from England while travellers to amber countries have to isolate at home on their return. Flying from red list countries remains extremely restricted and passengers must quarantine at hotels for 10 days.
Even with passenger traffic running more than 90 per cent below normal levels, the Home Office expects border queues at airports to be longer.
"The traffic light system will make travel easier but it won't make it easy," said Rory Boland, the editor of consumer magazine Which? Travel.
"There's a considerable financial risk to travel this summer, especially over uncertainty about getting test results on time and what happens if you test positive."
But travel companies in the UK were still buoyant and extra flights are being allocated to green list nations.
Tui, the country's largest holiday firm, said it was adding new flights to green light countries such as Portugal.
"We've had the best day of sales for summer 2021 holidays since the initial road map announcement in February," a spokesperson said. "Sixty per cent of all holidays sold yesterday were to Portugal."
A spokesperson at industry giant Thomas Cook added: “Yesterday more people bought holidays to Portugal than had bought the whole of the rest of the year, but demand remains below normal levels and so hotels will have plenty of availability giving people plenty of choice.
"Customers are choosing to stay for longer than a week, and half of yesterday's Portugal bookings were in five-star hotels, showing that people are splashing out."
Ryanair, the low cost operator, said it will add 175,000 seats to the Portuguese destinations. British Airways also promised extra flights.
Travellers returning from amber countries, which include most of the UK's European neighbours, will be required to isolate at home for 10 days and take PCR Covid-19 tests on days two and eight.
The rules apply only to England, with Scotland, Wales and Northern Ireland administering their own systems.
Red-list status means that only UK or Irish residents can enter the country and returnees face a mandatory hotel stay costing £1,750 ($2,447).