Heathrow's chief railed against the quarantine place today warning there is a danger of the 'health pandemic becoming an unemployment pandemic'.
Home Secretary Priti Patel today insisted that a 14-day quarantine for UK arrivals is 'essential to save lives' - but confessed it would hit businesses hard.
She defied a significant Conservative revolt to tell MPs the blanket rule would come into force from Monday, with the next review new due to happen until the end of the month.
With just a few limited exceptions for lorry drivers and NHS workers, everyone coming to the country by plane, rail or sea will be ordered to give an address and self-isolate for two weeks, with spot checks from officials.
Heathrow boss John Holland Kaye said there had to be an 'exit plan' from the restrictions to avert huge redundancies.
'If we don't get a plan from the Government in the next few days on how we are going to reopen the economy, those jobs are at risk,' he said.
Home Secretary Priti Patel today insisted that a 14-day quarantine for UK arrivals is 'essential to save lives' - but confessed it would hit businesses hard
'I am going to have to make that decision in the next few weeks about jobs in my own company.
'We need to stop this health pandemic becoming an unemployment pandemic.'
Ryanair has described the UK's quarantine as 'utterly ineffective', claiming people can be playing golf or lying on a beach when telephone checks are made.
The airline claimed quarantines can only work when passengers are 'detained' at their point of arrival.
It said in a statement that the UK plans to allow people to travel on public transport across the country, and there is 'nothing to stop' them shopping in a supermarket to collect groceries before their 14-day quarantine begins.
The airline went on: 'Once they have arrived at their 'quarantine address', the UK Government will phone less than 1% of these visitors but only on their mobile phone, which can be answered from any golf course, beach, park or indeed supermarket across the UK, thereby rendering this quarantine utterly ineffective and useless.
'For the UK to be imposing a 14-day quarantine on inbound visitors when it already has one of the worst Covid infection and death rates in Europe, is closing the door long after the horse has bolted.
Ryanair has described the UK's quarantine as 'utterly ineffective', claiming people can be playing golf or lying on a beach when telephone checks are made
'Most visitors to the UK from Europe are arriving from countries with a lower R rate than the UK.'
A spokesman for trade body Airlines UK, which represents UK carriers, said: 'We need to see much more clarity on air bridges over the coming days.
'The key thing is that they are established as soon as possible alongside the FCO (Foreign and Commonwealth Office) travel advice being changed, and ideally before the review on June 29.
'Airlines can't start up operations overnight and any announcement isn't going to trigger bookings and flights for several weeks.
'If Government leave it too late we run the risk of the summer season being over and losing out to other countries who are starting to open up their borders now.'
George Morgan-Grenville, chief executive of tour operator Red Savannah, said: 'It is clear that (Home Secretary) Priti Patel has neither listened to the concerns of the travel industry, nor seems unduly bothered by them.
'We are none the wiser as to the science behind the rationale for quarantine and we still don't know what the 'enhanced border measures' in March actually achieved.
'But what we do know, is that 'Global Britain' is shut for business.
Heathrow boss John Holland Kaye said there had to be an 'exit plan' from the restrictions to avert huge redundancies
'It is the wrong policy that is going to cause untold misery for hundreds of thousands of people who will now very likely be made redundant.
'The Government are responsible for lives and livelihoods. Has the Home Secretary thought about what the loss of livelihood is going to do to the lives of so many people across the UK travel and hospitality industry?
'She must now take responsibility for the consequences.'
In a glimmer of hope for airlines, it has emerged that commercial flights will resume at London City Airport by the end of June.
Domestic routes will be the first to restart, with international flights 'depending on the proposed quarantine of passengers arriving into the UK', according to a statement.
London City's runway has been closed to commercial and private flights since March 25 due to travel restrictions and the collapse in demand.
Mr Holland Kaye said 'nobody is going to fly' if there is a quarantine in place, which means that not only will Britons not be able to take summer holidays abroad, but we will not have access to trade that happens on passenger flights to Heathrow.
While the Home Secretary was adamant the clampdown was 'proportionate' to ensure coronavirus did not spike again, Ms Patel did raise hopes by saying the government is looking at 'international travel corridors' to low infection countries in the future.
Another business leader, Catherine McGuiness, policy chair at the City of London Corporation, told City AM the plans would have 'a major impact on a range of sectors, including the City's financial and professional services firms as well as our cultural institutions'.
She said rules that seemed 'arbitrary rather than consistent undermine confidence and will hold us back', suggesting that the government adopt an 'internationally coordinated approach' to organise passengers flying as soon as possible.
Ms McGuiness said 'air bridges' to countries that have a lower infection rate could be a possibility.
Chief executive of the London Chamber of Commerce Richard Burge said that the quarantine sent out a message that Britain 'is closed for business' at a time when we are only just restarting our economy.
In a letter to members of the government, he said: 'This blanket aviation proposal doesn't appear to be risk-based.
'If it was, it would recognise that arrivals from some countries with much lower transmission levels than the UK and low incidence of the disease would not increase our risk, provided they adopted our social distancing protocols on arrival'.