Align to Path Expression

If you have created an animation path for an object (e.g. an airplane), it is very tedious to use additional rotation keys to set the orientation of the object so that it always moves tangentially to the defined path. With the Align to Path expression, you achieve that the object follows the animation path with its Z-axis, which you have created with the Position track or by keyframing.

Example

In the following scene, 2 exclusively position-animated airplanes are flying. Top with, bottom without Align to Path expression.

The X-axis of the object is always kept parallel to the XZ world coordinate plane. The airplane (or a camera) thus follows the natural course of movement.