re: speed limits in the sky (no Alfa content)

[Simon Favre <simon@domain.elided>]

There are always exceptions. When the SR-71 Blackbirds routinely flew,
they had to get special handling in controlled airspace. Every time one
had to pass through controlled airspace, there was a non-descript fellow
in an ill-fitting suit standing behind the air traffic controller to make
sure the necessary permissions were granted. Their stall speed is not far
below the top speed of the KC-135 tanker they had to link up with. There
was a story about an SR-71 pilot calling in for permission:

Pilot: "Request permission to fly through your air space to 70,000 feet, 
       at Mach 3, over."
Controller: "Son, if you can take 'em, you can have 'em."

Things were even more hairy on descent. Come down too fast, and you might
overheat the airframe, too slow, and you could run out of fuel before you
meet the tanker. Everything about those planes had to be done with great
precision. Another fabled radio exchange:

Pilot: "Request permission to descend through your airspace, over."
Controller: "Permission denied, please hold."
Pilot: "No, sir, you don't understand the mechanics of Mach 3 flight. I
       AM coming down NOW."

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