Beijing Capital International Airport welcomed its 80 millionth passenger this year on Wednesday, reaching its designed capacity five years ahead of schedule.

It remains the world's second-largest airport in terms of passenger traffic, trailing only Hartsfield-Jackson Atlanta International Airport in the United States, which handles nearly 90 million passengers a year.

Passengers wait in lines to check in at Terminal 3 at Beijing Capital International Airport earlier this year. Zhuo Ensen / for China Daily

Wang Yi, the 80 millionth passenger at the capital airport this year, arrived on a China Southern Airlines flight from Guangzhou at noon. When asked how he felt about the airport, he said it is "a little bit crowded".

Industry insiders said "crowded" will be the word that passengers think of when they walk into the capital airport, before the second capital airport of Beijing opens around 2018.

The airport estimated it will handle 81.6 million passengers this year.

It took just two years for the number of passengers to increase from 70 million a year in 2010 to 80 million this year, and the airport estimates that the yearly total will exceed 90 million by 2015.

The second capital airport, which is expected to divert much of the growing traffic, will not open for another five or six years, according to Li Jiaxiang, head of the Civil Aviation Administration of China.

"We have to come to a point that, whether willingly or not, we must come up with new plans to solve the problem along with the rapid growth of air traffic," Zhang Guanghui, general manager of the capital airport, said on Wednesday.