More than 22 million passengers have used Stansted in that last 12 months – the first time this figure has been reached in over six years.
The landmark comes just eight months since passing the 20 million a year milestone, with passengers up by 15.8% in the last 12 months.
September passenger figures increased by 9% over the same month last year as the airport served over two million passengers for the fifth consecutive month, the first time this has been achieved since 2008.
The month also saw the highest ever average load factor for any September at Stansted with 87.8% of all seats occupied on each flight.
The top five busiest routes last month were Dublin, Edinburgh and Glasgow followed by Barcelona and Rome.
Managing director, Andrew Harrison, said: “The rapid and sustained growth we have experienced at Stansted since the airport was acquired by MAG (Manchester Airports Group) has now seen us pass 22 million passengers a year for the first time since January 2009.
“To reach this milestone having begun the year at just below 20 million passengers is a fantastic achievement and testament to the strength of our catchment area as well as the continuing popularity of the airport’s extensive route network that serves 170 destinations – and more scheduled European destinations than any other UK airport.
“The extremely busy summer season has continued into the start of autumn with more than two million passengers again using the airport in the month, and the number of passengers travelling on each flight at record levels for any September in the airport’s history.”