Although Tokyo's Haneda Airport celebrated the first anniversary of the opening of its international passenger terminal Friday, the airport has a long way to go before it can be termed truly international.

The opening of the terminal was aimed at making the airport more convenient for people on overseas business trips and transit passengers, but the growth of passenger numbers remains sluggish because of the small number of international arrival and departure slots and the drop in demand after the Great East Japan Earthquake.

All Nippon Airways President Shinichiro Ito, however, appeared optimistic that Haneda would become more popular.

At a press conference in Tokyo on Thursday, he said flights to and from Haneda were generally full and transfers from domestic to international flights at the airport were increasing.

Despite his stamp of approval, only about 20 percent of international air passengers have switched to Haneda from Narita Airport, a far from satisfactory outcome following the trumpeting of the new terminal's opening, which was expected to increase users at both airports.

Except for April, immediately after the March 11 disaster, the number of people using Haneda since November last year hovered between 500,000 and 700,000 a month.

While 696,200 people were estimated to have passed through Haneda in August, traffic at Narita the same month was down 17 percent year-on-year, at 2.13 million people.

Besides the small number of international slots, the sluggish growth of passengers at Haneda Airport also is caused by the late evening and early morning times that airlines serving Europe and United States have to adhere to. These times are set by the government to ensure Haneda can coexist with Narita, which does not allow planes to arrive or depart at night.

From 6 a.m. to 11 p.m., airlines can fly only short distances to neighboring countries from Haneda, and the 32 international slots for this period have been filled.

However, only 18 of 40 international slots are being used for the 11 p.m.-6 a.m. period, when public transport linking the airport and main metropolitan areas is limited.

Currently, there are 371,000 arrival and departure slots per year, including about 60,000 international ones, at Haneda Airport. These are expected to increase to 447,000, including 90,000 international one, by the end of March 2014.

Since this increase is expected to involve international flights during the 6 a.m.-11 p.m. period, it remains to be seen whether flights to and from Europe and the United States will affect overall airport use.

The government's growth strategy for Haneda aims at increasing international services.

Takashi Okada, chief researcher at the Japan Research Institute, said, "It is necessary to increase the number of flights linking Haneda to major cities in Europe and the United States during the set time zone, while increasing the value of the airport by building hotels near the airport and developing surrounding areas."