Bell X-1 "Glamorous Glennis" (signed)X 1 Signed by Yeager model. Next to the Wright Brother's Kitty Hawk flyer, the X 1 is probably the second most important and historical aircraft to have flown. The diminutive Bell X 1 rocket research plane was the world's first aircraft to break the "sound barrier" and achieve supersonic flight. On October 14, 1947, the X 1 named "Glamorous Glennis" passed Mach 1 on its epic flight and was piloted by Chuck Yeager. The aircraft's conical nose was