Jumping side kick:
Face sideways to your opponent. In other words, your partner is on your left or right side. With minimal leg bending, spring up with both feet and tuck your legs into your stomach. Quickly shoot your left or right foot out in a side kick. Your other leg can remain tucked in or dangle. The faster you jump, the higher you will go. The higher you go, the more time you have to do the kick, which must still be fast. The standing jumping side kick is used defensively. If you cannot do a standing kick well, do not do jumping kicks. You will lose your balance, fall, and hurt yourself.
Flying Side kick:
From a fighting stance, advance forward several steps. Walk first, then speed into a run, lengthening your steps. Plant your left foot onto the floor, pushing your body into the air. As you jump, torque your body over sideways, cocking your right leg into your stomach. As you shoot the right leg into a side kick, tuck your left leg under your body. The longer and faster your step, the more distance you cover. The faster you push yourself into the air, the higher you go. This kick is primarily offensive, designed to cover distance, jump over obstacles, gain height etc. Same rule applies: Get your basics down first.