Hong Kong-based carriers, including Cathay Pacific Airways, are being urged by the Civil Aviation Department to use larger aircraft and consolidate routes as the airport risks running out of landing slots as early as next year.
The airport is now seeing 65 take-offs and landings an hour during peak operating hours from 10am to 1pm, the maximum number allowed on its two runways.
"The hourly capacity of the two runways is expected to increase to 68 movements in 2015 during certain busy hours of the day, while room for substantially lifting the capacity would be limited," said Raymond Li, the aviation department's chief air traffic control officer.
"Only one to two additional slots could be added after the upgrading programme of the air traffic management system is finished."
The air navigation system is migrating from a ground-based radar to a satellite-based system to increase air traffic control capabilities within the 200 nautical mile radius controlled by Hong Kong and to boost capacity.
The present movement cap at Chek Lap Kok has often been criticised, as the number appears to be short of international standards. For example, the two runways at London Heathrow Airport can handle more than 80 aircraft an hour.
But Li said the presence of Lantau Peak to the south and the mix of aircraft types in Hong Kong had an impact on runway capacity.
The ratio of wide-body aircraft in Hong Kong, 65 per cent to 70 per cent of the total, was much higher than at Heathrow, and they required a separation of 90 to 120 seconds for landing and taking off, while narrow-body aircraft needed just 60 to 70 seconds, he said.
"In the meantime, we are in talks with the Airport Authority and airlines to increase the capacity of the airport in light of the runway constraints," Li said.
The Airport Authority has kicked off projects to provide more parking spaces for aircraft and a new mid-field concourse will be finished next year.
Li said airlines were being urged to adjust their business plans accordingly, including using larger aircraft and focusing more on popular destinations.
Cathay Pacific has placed orders for 102 passenger aircraft since 2010, 67 of them with 315 to 400 seats, including Airbus 350-900s, A350-1000s and Boeing 777-9Xs, the airline said in December last year.
"Capacity constraints at Hong Kong airport have always been an issue as the airport is now approaching its maximum runway capacity," a Cathay spokesman said. "This makes the development of a third runway at the airport urgent and essential."
One airline executive has suggested a radical solution to the peak hour problem. Airlines should be allowed to bid for the best time slots, as was done at Heathrow, Hong Kong Express Airways deputy chief executive Andrew Cowen said.
But analysts said that would be a last resort move because of objections from incumbent airlines.