The London Assembly has called on the government to improve transport links at the city's airports.
Specifically, it wants a new strategy to improve surface transport - with a strong emphasis on rail connections - to and from airports.
Chair of the London Assembly's transport committee Val Shawcross said: "Luton, Stansted and Gatwick all have spare airport capacity that might prove useful to determining the UK's future aviation policy."
In it's report, 'Airport Capacity in London', the committee states Luton, Gatwick and Stansted all have capacity for additional services. It argues poor transport connections are putting people off.
It states one out of every six trains to Stansted face delays of at least ten minutes. At Heathrow in 2010, 26 per cent of passengers used a taxi and 31 per cent used a private car.
A suggestion has been made for airlines to better inform customers on rail travel - the committee argues many assume car travel is faster due to a lack of better knowledge.
The assembly has written a letter to Sir Howard Davies, chair of the Airport's Commission, expressing the impact of possible changes.