The City Airport suffered the least dramatic fall in passengers
The number of passengers using Northern Ireland's airports has fallen sharply compared to this time last year.
The biggest fall was at City of Derry which had 36.2% fewer passengers than in March last year.
The falls at Belfast City and the International were 7.5% and 21% respectively.
The provisional figures from the Civil Aviation Authority show that the most dramatic slowdown is in the number of people taking international flights.
In March, the CAA's figures showed that passenger numbers at UK airports fell last year for the first time in 17 years.
About 4.6m fewer people flew in and out of the UK in 2008 than in 2007. The last time numbers fell was in 1991.
The decline was particularly sharp at the end of the year, with passenger numbers dropping 8.9% in November and 7.9% in December, compared with 2007.
The falls were expected to continue during 2009, the authority said.
Earlier this month the Airport Operators Association (AOA) warned that some regional airports could struggle to survive the recession because of falling passenger numbers.
The AOA blamed budget carriers for squeezing costs, but airlines say extra charges have forced travellers away.
Airports have insisted that a shortfall in income has forced them to introduce extra charges for services such as fast-track security or car drop-offs for passengers.