You are not alone.
Let's be honest, women flake. And they don't only flake on guys. They flake on their girlfriends, co-workers, pretty much anyone with whom they might make plans. That's just what they do. They eat, sleep, f*ck and flake.
If they flake on the first or second date, they will flake constantly to the point where you will have "plans" every week or so, but never see them. And the only real way to avoid this is to prevent or discourage it in the first place. You need to show them that it is irresponsible behavior and not something you will accept from someone you choose to spend your time with.
If she says, "Call me a couple of days before to figure out the details," I say "We just figured out the details. Mark it down on your calendar and I'll call you when I'm leaving to pick you up, meet out, etc." If she says, "I might have to blah, blah, blah," I say "Sounds like a bad time for you, I have to run but I'll call you in a few days to figure out when we're both free."
This is not to say women don't flake on me. As I said, it's just one of the things that they do. They put as much though into flaking as, say, taking a shower. And they don't even realize it. That's how ingrained it is. But if they do flake on me, they won't have an opportunity to a second time.
I ran into a girl a month or so after she flaked on me the first time we made plans. She asked why I never called her again. I told her she flaked on me and I don't have the time to deal with people who don't respect my time. I don't remember her exact excuse, but it was something like "I didn't flake, I had to go out for drinks with a friend of mine." lmao
That's the attitude we're dealing with.
There is a distinction, however, between flaking and legitimate reasons to change or cancel plans. And you should be able to tell which is the case just by the conversation. If she says someting like "Oh, I told my friend I'd go to..." that's a flake. If she sends you a text instead of calling, that's most likely a flake, too. If she's sick, has a business meeting, family event or something along those lines and calls to reschedule, that's cool. But if these things are popping up all the time, that's right... flake.
All you can do is move on.