British Airways, bmi, easyJet and Virgin Atlantic urged the government to take "urgent action" to ensure regular scheduled flights get through the increase in air traffic surrounding the London Games, which run from July 27 to August 12.
Chiefs from the four airlines cited industry concerns about the "lack of capacity", in a joint letter to the Department for Transport (DfT) and the Civil Aviation Authority, which regulates aviation in Britain.
New measures "are essential if we want to minimise the impact to the travelling public of both the anticipated increase in air traffic due to the Games and the current lack of airspace resilience in the southeast," they said.
"The industry believes that there is a significant risk of severe delay and disruption at all of London's major airports unless urgent action is taken.
"Time is running out to ensure that any changes to procedures and the appropriate training is in place."
Failure to act would leave Britain vulnerable "to the type of major disruption that will cause significant reputational damage and would be fool-hardy and reckless.
"We encourage you both to ensure that the appropriate action is taken to enable the industry to deliver the service that is so critical to the success of London 2012."
London Heathrow is the world's busiest international passenger airport, while London Gatwick is the world's busiest single runway airport.
London Stansted and London Luton are among Europe's top 50 busiest passenger air hubs.
"The government is committed to delivering safe and efficient transport services for the 2012 London Olympic Games, and aviation is clearly a major part of this," a DfT spokeswoman said.
"That is why we have already announced a range of special measures designed to protect scheduled air services from disruption during the Olympics period."