3 – Getting into the air
In order for a plane to take off, a strong air circulation facing the plane is needed.
That is why engine are turned on, so the plane get some thrust that in turn will create the lift needed for the plane to take off.
The lift will compensate the weight of the plane and the plane will fly.
Once in the air, drag will appear slowing down the plane that is why more thrust is needed to compensate the drag.
The plane is staying in the air because of the balance: Thrust <–>Drag and Lift <–>Weight
Source: quest.nasa.gov
