Unions and politicians have reacted with fury over the collapse of Flybe just weeks after the company narrowly avoided going under in January.
A drop in demand caused by the coronavirus "made a difficult situation worse" for Flybe, an airline source told the PA news agency, and although crisis talks were held throughout Wednesday to try to secure a rescue package, no deal could be agreed.
The end of the Exeter-based airline will threaten thousands of jobs and the future of a number of regional airports.
Unite national officer Oliver Richardson told the PA news agency: "Unite members and the entire staff at Flybe, will be feeling angry and confused about how and why the airline has been allowed to collapse.
"It is simply outrageous that the government has not learned the lessons following the collapse of both Monarch and Thomas Cook that the much promised airline insolvency review has still not materialised.
"While other European countries are able to introduce measures to keep airlines flying when they enter administration, the UK remains unable or unwilling to do so.
"The UK economy is highly dependent on a viable and supported regional airline and airport network. For central government not to support and nurture this, especially as we deal with the twin uncertainties of the Covid-19 virus and the changes that will come with Brexit, is unhelpful and irresponsible.
"Other major airlines have repeatedly said that they are ready and willing to organise flights on Flybe's routes and for the sake of the passengers and communities that the airline served, the government must ensure that those commitments become reality.
"Unite will be providing advice and assistance to our members to help them at this highly difficult time."
Andy McDonald, Shadow Transport Secretary, said the loss of Flybe would cause "real anxiety" throughout the country.
He said: "The Civil Aviation Authority is sadly very well practised, following the collapse of Monarch and Thomas Cook, at responding to airline failure and looking after passengers. No doubt they will do that once more.
"Yet again more airline workers face an anxious future and the Government has to respond and provide them with all necessary support.
"Flybe has provided critical connectivity for many locations throughout the country especially where there is currently no realistic transport alternative other than flying.
"The Government has to answer how those vital links will be maintained following Flybe's collapse. Communities will be concerned about what this will mean for their local economies and the Secretary of State has to come up with answers to these questions as a matter of urgency."
Rory Boland, the travel editor at consumer group Which?, said oil prices, Brexit and the coronavirus had all contributed to a collapse which surprised few people in the industry.
"It has been a turbulent couple of years for airlines. Not just regional airlines, we've seen dozens go under, not just in the UK but across Europe," Mr Boland told the BBC.
"Bouncing around oil prices haven't helped, Brexit has also had an impact.
"Flybe would point at least some of the blame to air passenger duty and it seems the coronavirus has just slightly pushed (Flybe) over the edge, but it has been struggling for many, many years, and I don't think it will come as a huge surprise to lots of people in the travel industry that it's going under."