I looked up for some information on OBEs and noticed some similiarities with the dream i had (the sound & waking up to it).
In the dream the sound I heard was a mixture of humming and my ears ringing, but like I said it didn't start until I was in the air.. So yeah, it could be that I'm still too unfamiliar with the whole thing.

Anyways, thanks for the replys. I'll try to avoid running next time.