Aberdeen International Airport (AIA) suffered a near 17% fall in passenger numbers in January as reduced offshore helicopter business continued to hit the terminal.
The north-east gateway was used by a total of 210,021 people last month, compared with 252,561 the previous January.
Bosses said a sharp fall in the number of people using domestic fixed wing flights – last month’s figure of 117,850 was down by 20% year-on-year – also contributed to the overall drop in travellers.
Domestic services have been hit by Virgin Atlantic withdrawing its Liddle Red service between Aberdeen and London Heathrow last autumn.
The ongoing impact of a severe downturn in the North Sea oil and gas industry saw AIA suffer a 24.5% drop in helicopter passengers last month, compared with January 2015, while international flights carried 3.7% fewer passengers.
AIA managing director Carol Benzie said: “The low oil price is continuing to have a direct impact on helicopter and domestic traffic.
“Despite showing a slight dip, international traffic remains strong and we have the launch of Icelandair’s new year-round service to Reykjavik to look forward to in March.”
She added: “January brought welcome news and a much-needed boost for Aberdeen in the shape of the City Deal announcement.
“The scale of the investment, coupled with the news that we are to significantly expand the airport, presents a fantastic opportunity to deliver a real step change for Aberdeen in terms of improving infrastructure, strengthening our economy and bolstering the labour market.”
Plans for a £20million expansion of AIA were officially unveiled by First Minister Nicola Sturgeon last week.
The SNP leader jetted into Aberdeen to formally announce details of the redevelopment, which is expected to increase the size of the airport by half.
A two-storey extension willl include two passenger lounges and expanded baggage reclaim, security, and immigration areas. Also included in the revamped facility will be new retail and food outlets.
Meanwhile, the number of people passing through Edinburgh Airport increased by 11.4% to 700,142 last month after a jump in international passengers.
Glasgow Airport welcomed 551,177 passengers last month, up 13.5% on the previous year.