The volcanic ash cloud and industrial action by BA cabin crew hit passenger numbers at Scotland's airports in May.
Glasgow was worst affected, with passenger numbers down 13.7% on the same month last year.
Edinburgh saw a fall of 11.6% and passenger numbers dropped by 9.9% at Aberdeen.
In total, BAA's three Scottish airports handled more than 1.5 million passengers in the month - a drop of 12.1% on last May.
The airport operator BAA said that without the disruption it expected numbers would have increased by 0.4% at its six airports during May.
There was also a fall of 7.1% at the Scottish airports in the year to the end of May, although 18 million passengers still passed through them during that time.
Glasgow saw the biggest annual fall of all BAA's airports - down 11.7%.
BAA - which is majority-owned by Spanish firm Ferrovial - sold Gatwick for £1.5bn last year.
British Airways cabin crew walked out for a total of six days during May as part of a long-running industrial dispute.
Meanwhile, Ryanair has announced increased frequencies on some of its flights from Edinburgh.
From November, there will be more flights to Alicante, Barcelona, Brussels, Frankfurt and Malaga.
Ryanair said the expansion would increase the number of passengers flying from Edinburgh from 1.5 million to 2.5 million.
The company has significantly increased the number of routes from Edinburgh in recent years and now operates 39 from the capital and 26 from Prestwick.
Following reports that Ryanair planned to significantly reduce routes from its Prestwick airport, the company said it was still committed to the Ayrshire hub.
Laszlo Tamas, a senior manager at Ryanair, said: "We are still obviously committed to Prestwick, but we are working very closely with Edinburgh airport and of course they offered us very good charges which for us is of key relevance."