Originally Posted by
ORAC
The same reason they trialled dropping one out if the back of a C-5 - airborne alert.
My first thought was that using a Mach 3 bomber to launch an ICBM would be serious overkill, but then I remember that - at the time it was being tested - it was far and away the largest aircraft flying - something like 250 tons.
The C5 and 747 came along a few years later.