Alright kiddo, imagine you have a toy plane. It can fly really fast and take you from one place to another. Now, imagine there are even cooler planes that are like your toy plane but they are bigger, faster and carry more people. These are called jets.
Now, a very light jet is a type of jet that is smaller than the normal jets you see in the sky. They are still fast and can take you to other places quickly, but they are designed to carry only a few people. They are also lighter in weight, which means they can fly farther without needing to stop and get more gas.
People use very light jets for business trips, vacations or if they just want to go somewhere quickly. They are like a fancy car, but for the sky!