The word meditation can be used in different ways for a lot of people. You can use it to contemplate a certain idea or thought (I would rather like to call that critical thinking), you can use it to empower certain emotions you want to feel either for yourself, or another (I would rather call that prayer). There are many different variances of how the word meditation is used, but in my opinion, there is only one true way of meditation.
No mind, no thought, no desire, no self, no ego state.
Our dreams are projections of our ego state, our desires and thoughts, our hopes and fears. This is exactly the opposite of what we are trying to accomplish while meditating.
One thing you can try, and i would advise, is to try meditation WHILE you are copletely lucid in your dream. Every time i do, i end up waking myself up soon after. For some reason it won't let me stay in the dream if i attempt no-thought meditation whilst being lucid.
So i don't think lucid dreaming is a form of meditation, i think it is a form of controlled thought, awareness and concentration... i know from experience it is possible to meditate while you are lucid in a dream, at least for a time... but it's hard to practice that when you just want to take off flying.