As many as 270,000 people are set to fly out of the UK to 'amber list' countries by Sunday after ministers insisted holidays in Spain and France remain off limits.
England relaxed a wave of lockdown restrictions that had been put in place to tackle the spread of Covid on Monday, giving the green light to holidays abroad.
Among the raft of changes was the re-opening of foreign travel but just 12 countries have been put on a green list, which includes Portugal, meaning tourists flying back home won't need to quarantine.
Most of Europe is on the mid-tier amber list which means passengers arriving back in the UK are required to self-isolate for 10 days and take two Covid tests.
It comes after a series of mixed messages over holidays from Tory ministers with the government telling people not to go on holiday to amber nations - but it's not illegal.
More than 1,300 flights are scheduled to fly out to amber countries in the five days to Sunday, reports the Daily Telegraph.
This is said to be at a rate of up to 54,000 passengers a day, with destinations including holiday hotspots like Spain, Greece, Italy and France.
Cirium, a global aviation data firm, reportedly said the number of scheduled flights and passengers to Italy, Greece and Spain was set to increase by up to 200 per cent in the coming days.
This is said to represent a doubling to Spain, from 38 flights on Wednesday to 80 on Saturday, with capacity for up to 16,000 travellers.
It would also be a trebling to Italy from six to 19, carrying up to 3,400 passengers, with demand for France flights rising from six to 10.
This week Environment Secretary George Eustice said people could go to amber-listed countries to visit family or friends as long as they observed quarantine rules on their return, while Welsh Secretary Simon Hart said "some people might think a holiday is essential" and therefore a valid reason to travel.
The Prime Minister has insisted the position over holidays is "very clear" and people should only travel to an amber list country "for some extreme circumstance, such as the serious illness of a family member".
"You should not be going to an amber list country on holiday," the Prime Minister told MPs.
Senior Labour MP Yvette Cooper says the Government needed to be "much more cautious" about re-opening travel abroad and warned re-starting foreign trips should be halted amid mounting fears over the spread of the Indian Covid variant.
Yvette Cooper said the Government needed to be "much more cautious" about re-opening travel abroad.
Health Secretary Mr Hancock told a Downing Street press conference: "We have been absolutely crystal clear that you should not go to an amber or red list country on holiday, you should only go in exceptional circumstances."
But Mr Hancock added "you don't necessarily have to ban everything" even if the Government advised against it.
He told Times Radio: "People should not travel to amber or red list countries unless it’s absolutely necessary, and certainly not for holiday purposes."
Meanwhile Ryanair boss Michael O'Leary said "most of the UK population doesn't understand" the rules on travelling to amber-listed destinations, with people "booking in their droves" to take holidays in places not on the green list this summer.
Travelling to amber list countries is allowed but Brits returning to England must book and pay for a number of Covid tests and obey a period of quarantine.
