The Irish Aviation Authority (IAA) says air traffic fell by 85% in April due to the coronavirus pandemic.
A total of 14,907 flights were handled by the authority last month - as against 96,131 in April last year.
While commercial traffic at State airports was down by 90%, and trans-Atlantic traffic dropped by 83%.
Dublin Airport recorded just 2,067 flights, an 89.8% decrease, while Cork Airport traffic fell by 93.9% and Shannon saw a 79.8% decrease.
IAA chief executive Peter Kearney said that while the collapse in air traffic levels has been swift, the IAA is hopeful that the decline has reached the bottom.
"As an island economy, Ireland is reliant on aviation for economic growth and prosperity.
"Aviation is an economic enabler and Ireland has become a major global player in the aviation sector.
"It is important therefore, if Ireland is to recover from the COVID-19 pandemic and return to growth, that we have a fully functioning and stable aviation industry."
“The traffic stats for April show the scale of the crisis which aviation is facing.
"However, the aviation sector has proved to be extremely resilient to downturns in the past; with the right measures in place aviation can start to re-open the world for Irish people again."
The IAA said a coordinated approach across Europe is needed to ensure aviation can re-open and passengers can be confident their flight will go ahead - and that risks associated with the coronavirus are minimised.
The European Commission published guidance on Wednesday in relation to re-opening aviation and tourism.