Guo Yongyi arrived at the Beijing Capital International Airport around 7:30 on a weekend morning.

As an unaccompanied child passenger, she was required to arrive at the airport at least one hour and a half before her flight was set to take off for Shenzhen, Guangdong province.

The 11-year-old will wore a special small paper bag around her neck, which shows her name, age, and the address of the person who will pick her up at Shenzhen airport. The bag also contains her ticket and ID card.

An escort was responsible to help Guo through check-in, security, and boarding procedure. A flight attendant took care of her during the journey. After her flight landed in Shenzhen, another airline employee helped Guo pick up her checked luggage and wait for parents to pick her up.

In the past few years, a growing number of children like Guo, between 5 to 12 years old, have been "mailed by air" through unaccompanied children service. Parents are increasingly caught up with work and lack the time needed to travel with their children.

Many airlines offer discounted tickets to children who are 12 years old and under. And the escort and guidance services provided by the airline staff are free of charge.

Related story: Flying solo

Photo gallary: Children "mailed by air"

Reporter: Guo Shuhan

Editor: Lin Hanqing

Videographer: Zhu Xingxin

Voiceover: Chris Clark

Producer: Flora Yue