Why does an aeroplane stay balanced in the sky?

Question: Why does an aeroplane stay balanced in the sky?
- Keywords:
  aeroplane,
  balance,
  sky
Asked by Achsu to Betty, Isaac, Kieran, Silvia, Will on 10 Nov 2016.
- Betty Bonnardel-Azzarelli answered on 10 Nov 2016:
  
  An aeroplane stays balanced in the sky because the forces which apply to it are balanced, it is stabilised with onboard instruments and the plane has a certain speed. The forces include drag and thrust.

Question: Why does an aeroplane stay balanced in the sky?