In August 1.4 million passengers used the airport, up 16% on the same period last year.
The airport is currently investing £100 million to increase the capacity from 12 to 18 million by 2026.
Nick Barton, the airport’s chief executive, said: “This record-breaking summer has demonstrated the increasing popularity of LLA and has highlighted the need for expansion in order to meet the demands of our passengers.
“The £100m we are investing will ensure that we are able to give all our passengers a quick, easy and good value service at London Luton.”
