That may just because you cut it short and your hair isn't long enough yet to weigh it down.
I have pretty short layers toward the top of my hair and if I don't straighten them, they curl upwards. But my hair is naturally a little curly. I've noticed that if I let it grow out, the weight of the hair will weigh it down and it will lay flat. The longer my hair is, the straighter it is, because the weight doesn't allow it to curl, if that makes sense.
So try to grow it out
until then, maybe straighten them?