How do induction helicopters work??

Recently i bought a induction helicopter from a local store for about 10 bucks. It came with a remote control which was rather hard to understand and a charger.

They have a hand sensor or a simple sensor on the bottom right next to its motor and it sensors when a hand comes nears it or right below are flies higher, when nothing is caught by then sensor it automatically lowers down.

This made me wonder How does this go higher. And this simple question has a simple answer. 

So first 
-Propellers spin fast (well obviously but there's more to it) When you turn it on, the motor spins the blades really fast. This creates lift (an upward force that pushes against gravity)

lift here plays a key role, its the main concept for the whole helicopter

-Air pressure difference. The spinning blades push air downward. That creates higher pressure below and lower pressure above. So the helicopter is lifted upward 

-Sensor tells it when to rise. Infrared sensor sees your hand or floor under it, It tells the motor: “Yo, increase speed”, Motor spins faster = more lift = it rises


So yeah, it’s not magic it’s physics.