<p>The coolest spy plane ever built, SR-71. I was watching Modern Marvels on the History channel last night. This aircraft broke all kinds of international speed and alitude records which still have not been beaten today. It was nothing for them to fly at 80,000 feet and it was a piece of cake to fly at about mach 3, or about 2100 mph. For those of you old enough, remember the sonic boom days? About 750 miles would create a sonic boom, or a doppler effect.</p>
