Heathrow will lose importance as a pan-European hub without the go-ahead for expansion.
Lord Clive Soley, chairman of lobby group Future Heathrow – a coalition of business groups and airlines – said: “The critical measure of a hub airport is not the number of passengers but the number of destinations served, and that is where Heathrow is losing out.
“In March, Munich overtook Heathrow in the number of destinations it serves, and Milan and Madrid will overtake Heathrow soon.”
He warned: “Businesses will begin moving away from the Thames Valley if the airport is not important enough.”
Heathrow’s network connections grew by 3.3% in the year to last August, according to Soley, compared with a 24.5% increase at Paris Charles de Gaulle, 17.5% growth at Amsterdam and 13% at Frankfurt.
Traffic movements at Heathrow are restricted to 85 an hour, compared with 120 at Paris CDG, Madrid and Amsterdam, and 100-120 at Frankfurt.
A third Heathrow runway would add 175,000 flights a year, allowing services to an additional 75-80 destinations, said Soley.
However, John Stewart, chairman of lobby group Transport 2000, dismissed the claims. He said: “There has been no study of the economic impact on London if Heathrow did not grow.
The comparison should be between all of London’s airports and their rivals.”