Luton airport recorded 16% more passengers last month to 1.3 million over July 2014.
The rise marked 16 months of consecutive growth as the airport as it plans for a £100 million upgrade to increase annual capacity from 12 million to 18 million passengers by 2026.
The airport has 19 new routes confirmed for 2015 including SunExpress starting flights to Izmir in Turkey last month.
Further new routes planned this year include Innsbruck and Vienna by easyJet and Tel Aviv and Ovda operated by Monarch Airlines.
Airport chief executive, Nick Barton, said: “We are on track for a record-breaking summer. The continuing growth in passenger numbers makes our £100 million redevelopment project essential to the role London Luton airport plays in easing capacity issues in the southeast of England.”