RadarGun

This is a very lightweight addon which tells you how fast you're going in a simple draggable frame. Indicated speed as well as true ground speed are both available. Pitch is also displayed with color coding.

Indicated speed is how fast you are going in whichever direction you are pointed. True speed is how fast you are going across the ground.

Right click to change between True ground speed or Indicated speed.

This is an ultralight addon which consumes about half of the memory what Titan Speed does. That's no easy feat!