This is a Banshee prototype, one of a couple of impressive Halo prototype toys shown at Toy Fair 2011. Most of what was in the Halo section of the McFarlane toy company's booth has a release date, but the best stuff, like this Covenant vehicle, isn't quite ready for production.
Another amazing prototype Halo toy. The McFarlane toy people say they still need to find out how much this one would cost. It sounds like they might have to simplify it a bit to make it affordable.