What force is responsible for making an airplane turn?

The horizontal component of lift is indeed the force responsible for making an airplane turn. When an aircraft banks into a turn, the lift vector tilts alongside the aircraft's wings. This change in orientation causes lift to have both vertical and horizontal components. The vertical component counteracts the weight of the airplane, allowing it to maintain altitude, while the horizontal component is directed towards the center of the turn. This horizontal lift component generates a side force that physically pulls the airplane into the turn.

Understanding how lift functions during turns is crucial for pilots because it highlights how banking the aircraft is essential for turning effectively and safely. While thrust provides the forward motion and weight acts downward due to gravity, it's the horizontal component of lift that enables the actual change in direction during flight.