The new three-runway system will enable more flights to and from Chek Lap Kok and will bring down air fares, Airport Authority chief Steven Yiu said on Friday.

All three runways came into operation on Thursday, with officials eyeing a boost in capacity to 120 million passengers per year.

Yiu, the authority's executive director, told RTHK that airlines are queuing up to get hold of additional departure and arrival slots.

"The airlines are excited about the three-runway system because they want to be able to operate more trips. If short-haul flights that take around four to five hours for a round-trip leave in the morning, that means they may be able to make three trips a day. From an operating point of view, this increases airlines' efficiency," he said.

Yiu said the authority is hoping to attract more airlines to use Hong Kong for lay overs and is hoping for more long-haul routes to be opened up.

"In the past six months, we have provided incentives to airlines if they are willing to provide flights to places that were not available before, or if they add flights to some of our strategic destinations," he said.

He added that Hong Kong will remain an international aviation hub even if competition from other airports in the Greater Bay Area intensifies.

"If we look at the economy in the Greater Bay Area, there is a total population of 86 million people, which is 10 times the Hong Kong population. The area also has the most vibrant economy in China. Even with the opening of all 11 runways in the area, I believe it will not be sufficient to satisfy all demand," he said.