Ryanair passenger numbers fell 99.5% in May, compared to the previous year.
The airline carried a total of 70,000 passengers last month, due to the collapse in air travel as a result of Covid-19 restrictions.
Ryanair operated just 701 scheduled flights in May, with a number of those being rescue and medical flights on behalf of various EU governments.
The airline said it expects minimal traffic again in June.
Earlier this month, Ryanair said it will resume operating up to 40% of its normal flight schedule from July 1.
The move is subject to restrictions on flights between EU countries being lifted and public health measures being put in place in airports.
In total the airline says it will run nearly 1,000 flights across 90% of the network it was operating prior to the Covid-19 crisis beginning.