The Earth has air around it, which causes air friction. This means that a sheet of paper or a piece of tissue paper will fall slowly through the air.
Which of these do you think will reach the ground first?
The flat piece of paper was slower because there is more air resistance.
This one is like a helicopter. There is a lot of air resistance, so it's slow.
How to make a paper aeroplane
Would you like to make a helicopter? I'll show you how. You need an A4 piece of paper.
You just need one quarter of the piece of paper, this strip at the end. Get some scissors. Now fold the strip in half. Cut along half of it. You don't cut the other side yet.
In the other half make two cuts a third of the way across. Don't cut too far. Fold the two thirds inwards over each other. Crease and secure with a paper clip. Bend open the helicopter blades. Now the helicopter is ready to fly.
Why not try making one yourself?