I'm pretty sure I saw the wings sweep forward as he entered the Denver Class B. When he was coming up from the south he looked a lot more sleek but as it headed over the east side of Centennial the wings were swung forward. I assume they sweep forward when it slows to a certain airspeed so that would make sense. Great looking jet and makes a distinctive sound too. The B2 just looks and gives you a creepy feeling when it flies over and the sound is missing. Uggghhhh!