Okay sweetie, so a liaison aircraft is kinda like a messenger plane. It's a type of airplane that's used to communicate and transport important people or things between different places. It's kind of like when your teacher sends a note to your parents with you to take home from school, but instead of you, the liaison aircraft carries the message or person.
Liaison aircrafts are really useful because they can fly pretty low and slow, making it easier for them to land and take off in smaller areas. They also don't need a long runway to land like bigger airplanes do. This means they can fly to places that bigger planes can't reach, making them really helpful in emergency situations or in war when soldiers need to quickly deliver messages or supplies to each other.
Sometimes, people also use liaison aircrafts for things like aerial photography, scientific research, or as a way to transport important officials to different locations. They're a pretty versatile and important type of airplane, even if they may not be as flashy or big as other types of planes you might see in movies!