Speaking to ITV’s Robert Peston, O’Leary revealed Ryanair forward bookings for November and December were currently at around 10% of normal volumes, figures he said were repeated "across most of the European and UK airline industry".
"It’s never been worse," said O’Leary. "We’ve never seen such awful forward bookings."
O’Leary urged the UK government to follow the EU’s lead, with the union hopeful of rolling out a regional travel plan from mid-October. O’Leary said this would open up the regions of dozens of EU countries.
"If we stick to the current UK scheme where the government adds Portugal one week and takes it off the next, nobody can make bookings with confidence," said O’Leary.
"I don’t think anyone can make travel plans with any certainty. What we need is certainty, the Europeans are at least trying to bring some certainty about from about the middle of October.
"We need this done on a regional basis not a national basis so fine, you may not be able to travel to Lisbon because its Covid rates are high, but you can still go to Faro because in the Algarve the rates are low.
"We need something much more sensible like that."
O’Leary said with the European Centre for Disease Prevention and Control set to start publishing regional Covid infection statistics on a weekly basis, there was no reason the UK government couldn’t work to these figures.
"Covid cases are rising in built up cities, not tourist destinations like the beaches of Spain and Italy," he said.
On testing, O’Leary highlighted how Italy and Germany has allowed intra-EU flights since 1 July while managing to keep their rates of new Covid infection below 20 per 100,000 people.
"In the UK, the government is mismanaging the situation," said O’Leary. "They’ve limited the number of flights people can take, and yet you are seeing huge Covid case rates here in the UK because you don’t have an effective test and trace system.
"Boris Johnson promised us world-leading test and tracing and like most of his promises, it’s turned out to be vacuous and completely undeliverable."
Looking ahead, O’Leary said he didn’t expect normality until a vaccine is discovered. "Clearly, we as an industry hope that will be in the early part of next year," he said.
"But in the meantime, we think Air Passenger Duty should be scrapped – you shouldn’t be taxing the few passengers who are travelling.
"The government needs to play its role. If Rishi Sunak can provide 50% Eat Out to Help Out discounts, the first thing he should be doing is reducing the high APD tax on air travel to and from the UK."