Actually, a feather floating by you gives you a bit of luck. It suppose to bring good news and fortune on the wind. If you have any of that then it is true.
It doesn't mean anything, except possibly that you may have a bit of a draught in your house. Feathers are so unbelievably light that they can easily give the impression of coming from nowhere, and of "traveling" along almost as if they were flying. In fact they are carried along on currents of air so mild that we often don't notice them at all.
A floating white feather means your guardian angel is close by