Strong performances at the most northerly airports have contributed to a rise of nearly 10% in the number of passengers using regional hubs last month, according to new figures.
Operator Hial handled 126,672 passengers overall in September, an increase of 11,229, or 9.7%, on the same month last year.
The group, which runs 11 airports in Scotland, pointed to "particularly strong growth" at Sumburgh Airport in Shetland and Wick John O'Groats, the UK's most northerly mainland airport.
Wick handled 4,634 passengers in September, up 119% compared with the same month last year.
Some 25,447 passed through Sumburgh Airport last month, up 58% on last year's figure.
Airline Loganair recently increased capacity between Wick John O'Groats and Edinburgh and is providing more flights between Sumburgh and Glasgow from November, Hial said.
Growth at Kirkwall, Inverness and Islay airports also contributed to the overall increase in passenger numbers.
But numbers were down at Barra, Benbecula, Campbeltown, Dundee, Stornoway and Tiree airports.
Dundee handled 2,461 passengers, down 53% on last year's September figure.
Looking at the overall picture, Inglis Lyon, managing director of Hial, said: "These figures are hugely encouraging, not least the boost in summer passenger numbers and the massive increase in demand for the Inverness to Amsterdam route, now in its third year, and still exceeding expectations. However, the drop in passenger numbers at many of our smaller airports illustrates that demand is not uniformly strong.
"We have added almost 50,000 extra passengers so far in this financial year which, given the distinct challenges some of our airports face, is particularly encouraging. Business and tourism growth is essential for the regional economy of Scotland, particularly in our more remote locations.
"In recent months, we have secured additional passenger services at Campbeltown, Inverness, Wick John O'Groats and Sumburgh and we are continuing to look at new opportunities for growth throughout the Hial group."