Free flight is like having a toy airplane that you can control by yourself without using any wires or remote control. It's really cool because you can make the airplane fly on its own! When you want to fly your airplane, you set it up and give it a little push to get it off the ground. After that, it's all up to the airplane to fly by itself until it lands on the ground. This is called "free flight."
But how does the airplane fly on its own? Well, it's because you have designed it to be very light and aerodynamic. This means that the airplane is built to be very streamlined and can move through the air easily. You also have to balance it just right to make sure it flies straight and doesn't crash.
When you're done flying your free flight airplane, you can go and find it wherever it landed. It's like having your own little pilotless airplane that you can play with whenever you want!