The budget carrier said on Wednesday (3 June) it expected "minimal" June carryings owing to ongoing restrictions on flying across Europe.
Group passenger numbers fell 99.5% in May to just 70,000; last May, the group – which includes Austrian subsidiary Lauda – flew 14.1 million passengers.
It operated just 701 scheduled flights in May, 1% of the 70,000 originally scheduled. This included a number of rescue and medical flights.
"Due to multiple EU government flight bans/restrictions, Ryanair expects minimal traffic in June," the carrier said in a note to the stock exchange on Wednesday.
Ryanair is planning to restore 40% of its normal July flight schedule from 1 July, with a number of EU states expected to reopen their borders over the coming weeks.
Chief executive Eddie Wilson said Italy, Cyprus, Greece, Portugal and Spain were poised to "reopen for holidays" after months of lockdown.