Help! I'm having trouble making my character fly

I’m fairly new to working in UE4, but I’m trying to create a 3rd person game where you fly around a city. I started with the third person template, created a small city, and added in the flying function where if you jump by pressing A and then press X while in the air your character will “fly”. X axis movement works exactly as if they are on the ground but the only way I can figure out how to add Y axis movement is by pressing a button (i.e. left trigger to go up, right trigger to go down). I’d like it to be where your character will move in any direction based on where the camera is looking. I’m having trouble figuring how a.) how do I make the camera stick to over-the-shoulder, and b.) how do I make them move up and down while flying based on the camera’s direction?

Any help or links to tutorials (i’ve watched so many but none address this specific scenario) would be greatly appreciated!

In the content examples of UE4 under the LEARN tab, there is a UFO game in which the UFO flies around the map.
You should maybe take a look at how that is laid out to get a better idea for your game.