Children aged 5 years old (inclusive) to 12 years old (exclusive) can fly alone by applying for the unaccompanied minor service, and children over 12 years old can fly alone. In order to ensure the safety and smooth travel of unaccompanied children, children aged 5 years or older but under 12 traveling alone must complete the relevant procedures for unaccompanied minor services before the airline can accept transportation. Aircraft: refers to a heavier-than-air aircraft that has a power plant with one or more engines to generate forward thrust or pull, and the fixed wings of the fuselage to generate lift, and flies in the atmosphere. The airplane is one of the most significant inventions in the early 20th century and is recognized as being invented by the Americans, the Wright brothers. Their flight on December 17, 1903 was recognized by the International Aeronautical Federation as "the first controlled sustained powered flight by a heavier-than-air aircraft" and in the same year they founded the "Wright Aircraft Company". Since the invention of the airplane, it has increasingly become an indispensable tool for modern civilization. It profoundly changed and affected people's lives and started the history of people's conquest of the blue sky.