Ryanair rejected new British government guidance for passengers to check in all luggage including hand bags, saying on Thursday it would instead recommend that passengers minimise checked-in luggage.
Britain published the guidance for airlines and airports on how to minimise the risks from coronavirus, adding to hopes that it will soon agree deals to allow quarantine-free travel.
Passengers and staff should wear face-coverings in airports and on aircraft, while passengers should check in all luggage and remain seated for as much of the flight as possible, the Department for Transport said.
But the guidance to put baggage in the hold drew a sharp rebuke from Ryanair. Europe's biggest low-cost airline said that unlike checked-in luggage, cabin bags are handled only by the passenger which limits any risk of physical contact with other people.
Ryanair said the government should focus their efforts on scrapping the quarantine on people arriving in Britain.
Since the outbreak of coronavirus, there has been minimal flying into and out of Britain. Airlines had been hoping for a recovery in July, but they say new UK rules requiring international arrivals to quarantine for 14-days have pushed this back.
Britain has said work is continuing on "air bridges" between countries with low infection rates, something which the industry says is vital to kickstart travel demand and avoid further job losses on top of the tens of thousands already announced.
"We are taking the necessary steps to ensure a framework is in place for the aviation industry to bounce back," said transport minister Grant Shapps in a statement.
Many airlines including easyJet, Ryanair and British Airways have already said that customers must wear face coverings onboard.