The price of a flight will go up if UK airports become too busy, aviation regulators have warned.
Capacity constraints at many airports will 'increasingly limit the choice and value available to consumers', the Civil Aviation Authority (CAA) told the Government, adding that air fares could 'increase significantly'.
The CAA said this was particularly true of south-east England, where the Government has ruled out expansion at Heathrow, the country's biggest airport.
In a report entitled Aviation Policy for Consumers, the CAA said the Government needed to put air passengers at the heart of its thinking when it consults on aviation policy next spring.
'Fares at congested airports are predicted to increase significantly as a result of capacity constraints,' the CAA report said.
It commented that such constraints could add £10 on a return fare by 2030, with a return at London City Airport going up by as much as £17.
CAA regulatory policy director Iain Osborne said: 'We frequently hear that the UK is losing out to Europe in its aviation network and that there is a connectivity crisis in London.
'The data we've published shows that there is no crisis today: London is one of the world's best connected cities and the UK punches well above its weight internationally in its air links.'
He went on: 'However, capacity constraints mean airports may become increasingly specialised in the routes they offer and the airlines that fly them. Government needs to recognise this and ensure that its aviation policy has the consumer interest at its heart.
'This review offers a chance to weigh up what approach to future airport capacity is likely to best serve UK passengers as a whole, rather than only considering what works well for south-east England.'
The report also warned that London's airports could find it harder to compete with those in other European cities as global economic activity shifts to emerging markets such as China, India and South America.
The study suggested that capacity constraints could mean there is more focus on 'the most profitable, high-yield routes' such as long-haul.
Airlines may also be less likely to 'take a chance' on launching services to emerging markets from Heathrow, the CAA added.