Ask him out. It's 2018. You can do that.
Ask him to coffee or a soda (not alcohol, not a meal). Have a lovely time. When done, say, "I had a great time. Let's do it again, but this time make it a real date. Are you free Saturday night?"
Or Friday or Sunday or whenever your schedule permits.
And see what happens. If he's still hemming and hawing, pin him down. Ask him outright: "I am getting mixed signals from you. It's confusing me. Do you want to go out, or not? Because if you don't, please let me know. And if you do, then do the same. In between is just confusing me."
If he still flakes, then do what you can to write him off.
I want you to know something. There are people who think that kind of flaky maybe yes, maybe no stuff is mysterious or fun or cute or whatever. Actually, it's passive-aggressive. It's the person hedging their bets, hoping to get something better but keeping you in their back pocket. And if for some reason they really are sincere that they don't know WTF they want, then I can assure you that you do not want to be with them, because that way leads to heartache when they change their fickle mind again and you're the one left feeling bereft.