If a comet looses energy in its trajecrory will it increase in Speed or decrease?

Answer 1

When anything looses kinetic energy its "speed" decreases.

Perhaps you're wondering about an object's speed if its orbital trajectory decreases. The answer is that a decrease in orbital trajectory indicates a decrease in kinetic energy & therefore speed. Vice versa, a decrease in speed will cause a drop in trajectory.

In an airplane pointing it down increases the plane's speed (its not in a orbit).