A three-year £160m transformation of London Luton Airport (LLA) is being officially opened.
The airport said the upgrade was the “biggest” in its 80-year history and would increase capacity by 50% allowing it to welcome 18m passengers by 2020.
It includes new shops, a new boarding pier, and more boarding gates.
Anti-noise campaigners said the upgrade “failed to reduce noise”, but LLA said it had applied for additional flight restrictions.
Andrew Lambourne, the chairman of Luton And District Association for the Control of Aircraft Noise (LADACAN), said: “The airport has failed to deliver on its promises in 2013 to reduce noise.
“The situation has now got so bad that it’s in breach of a key planning condition controlling the noise footprint, and is preparing to ask for it to be set aside for five years rather than actually solving the problem.
“Flights have increased by 90% on a key route. Commercial gain is trumping any kind of environmental responsibility at Luton.”
A spokesman for LLA said: “The growing demand for air travel has seen us marginally exceed our night time noise footprint by 1.5km².
“To address this and reduce our night time noise footprint immediate steps were taken to apply further restrictions on flights over the busy summer period.
“Our noise control measures are some of the most stringent of any major UK airport.”
The upgrade to the airport, which is owned by Luton Borough Council, also includes a new dual carriageway, a bus interchange and multi-storey car park.
The airport first opened on 16 July 1938 and the council plans to expand it further in a bid to attract 38m annual passengers by 2050.
Nick Barton, CEO of the airport said: “This is a new era for LLA. We are the fastest-growing major London airport and are now in a position to play an increasingly important role in the UK’s aviation network.”
Johan Lundgren, CEO, EasyJet, which is based at the airport, said: “This transformation project was a key factor in our commitment to long term growth at the airport.”
Work has also started on building a new £200m light rail system that will allow trains to run directly into the terminal. It is expected to be completed by 2021.