Hey xpgained, you could do it different ways, but the easiest way, would be to cast to your character BP, get the character movement component and off that get ‘Is Falling’. When you are in the air from falling or jumping, it will return true.
I also have a jump mechanic with a bool which is true when jumping and false when not, so I could also use this if need be. But in my case, my first option i mentioned works great for me.
Or you can do as clockwork says. There are a few options depending on what you need.