Flakepotomus
Someone who is a flake, constantly makes plans and then bails with little or no warning. People who are completely inconsiderate of other people, especially when time and scheduling is of importance.
That girl was the one with idea to go to this restaurant... now we are all here and she is a no show. The next time I saw her she gave me a big hug and fake kiss and acted like nothing had happened and we were all BFFs. What a flakepotomus!