Glasgow airport saw a record May with the number of passengers handled up by 5.5% to almost 830,000.
The year-on-year rise meant that the Scottish airport exceeded nine million passengers during a rolling 12-month period for the first time in its history.
Domestic and international traffic grew by 5% and 5.9% respectively last month.
Domestic numbers were boosted by the introduction of new Flybe services to Newquay, Cardiff and Exeter.
Demand for European destinations including Berlin, Milan, Bucharest and Budapest contributed to the increase in international passenger numbers.
Amanda McMillan, chief executive of AGS Airports and managing director of Glasgow airport, said: “Surpassing nine million passengers is a landmark for the airport and to have achieved this in our 50th anniversary year makes it particularly special.
“Our success in strengthening our connectivity with key European cities has generated significant demand from passengers which is reflected in May’s figures.
“We have always had a strong track record in long haul due to the huge population surrounding Glasgow Airport which provides a catchment of 2.3 million people.
“This is recognised by airlines and last month Air Transat launched its direct service to Montreal, Canada, in what was a first for Scotland.
“Air Canada Rouge will launch its direct flights to Toronto this month and we received welcome news that Delta will introduce flights to New York-JFK in 2017.
“These routes will play a major role in supporting our growing tourism industry and provide Scottish businesses with direct links to important global markets.”