For decades, experimental aircraft have pushed the envelope. Some led to classic designs, while others became historical footnotes. Here are a few.
The U.S. strike on Iran's nuclear development facilities saw the first use of the GBU-57 Massive Ordnance Penetrator, a weapon specifically designed for such a mission more than 20 years ago. The Air Force B-2s were the only platform with the stealth and carrying capacity needed to haul the huge…