Irish airports are among Europe's hardest-hit by the pandemic, and a major aviation body has warned their recovery could take until 2023.
The airports have suffered a collapse in passenger numbers of more than 98pc.
And the UK's "blunt instrument" deployment of quarantine as a control measure also threatens to inflict damage the sector will take years to recover from.
While Ireland, the Channel Islands and the Isle of Man have been exempted from the UK's controversial 14-day quarantine demand for all air travellers, Airports Council International (ACI) says it threatens to inflict not just an economic but a social blow to an already reeling industry.
"Most national authorities are quite rightly taking a phased approach but it is vitally important devices such as quarantine are risk-based and proportionate," warned ACI director general Olivier Jankovec.
"If quarantine is used as a blunt instrument as it is in the UK, it is one which will deliver an economic and social blow from which we will all struggle to recover."
ACI said just 4.3 million passengers travelled through its 500 European member airports in May, compared with 216.8 million in May 2019.
"With well over half a billion passengers lost so far this year and still no revenues coming in, Europe's airports are anxiously waiting for travel restrictions to be lifted and airlines to resume operations," said Mr Jankovec.
"With the epidemic now de-escalating in many countries and a plan to allow for intra-European travel - at least within the Schengen area - by the end of the month, we are finally seeing some light at the end of the tunnel.
"But there is no escape that the recovery will be slow and gradual - and that the post-Covid-19 aviation market will be fundamentally disrupted and structurally very different.
"For now, we do not see a return to last year's traffic volumes before 2023."
Dublin, Cork and Shannon airports have endured falls in passenger numbers of more than 98pc since March.
Ireland West-Knock airport has had to effectively shut down, while flights between Kerry and Donegal airports and Dublin have only been maintained through massive fare subsidies.
ACI is now calling on governments to acknowledge that airports need financial support as much as the struggling airlines which have received cash.
"Governments in Europe have almost exclusively helped airlines with more than €24bn of financial support already approved - and yet more to come," said Mr Jankovec.
The Dublin Airport Authority (DAA), which operates Dublin and Cork Airports, has urged all passengers to wear face masks and for only travellers to enter terminal buildings.
Enhanced deep cleaning of all airport facilities has been organised as well as the provision of 960 hand sanitisers, 720 protective plexiglass screens and 10,500 individual pieces of Covid-19 signage.
DAA chief Dalton Philips stressed safety was its priority.
Assumptions made by the Commission for Aviation Regulation last year when it determined the maximum passenger charges that can be levied at Dublin Airport from 2020 to 2024 are “no longer valid” in the face of the Covid-19 pandemic, according to its Commissioner, Cathy Mannion.