When you fight, put your hands up and chin down, that's great! You're protecting your face while fighting and you are in defending mode. Before getting into jump kick, let's see whether it is useful for self defense or not.
In common situations, you are not likely to do jump kicks and also flying kick. It depends on the situation. That might be some situations where it is better to do jump kick. For example, someone is about to hit your leg with stick. You can jump to save yourself. Instead of simply jumping, you can do jump kick.
You already hit the attacker before he is hitting you. So it is up to the situation and what you feel comfortable with. When you do jump kick, do not keep your face down. Look up, jump and kick. Well, you do not need to jump up to the sky.
You can watch this video. He explained and showed it very well. Hope you will find it useful. Thank you so much for reading this post. Please feel free to share your thoughts in the comment section.
Stay safe. Always be happy!