Hmmm…. I am a little shocked that people battle with this basic concept.
Oh, so do I.
Now, apply the same principle to an aircraft with a headwind component of 60kts with 60kts TAS. Ground speed is zero. The aircraft executes a max rate 180-degree turn. The aircraft now has to achieve a groundspeed of 120kts in the time it takes to complete 180 degrees.
Yes, it does. What you're neglecting is that what you call
inertia is actually
momentum, which is a vector quantity. That is to say it has a magnitude
and a direction.
An aircraft making a 180 degree turn in nil wind also undergoes a change in momentum of 120 knots (times the aircraft mass), from +60 knots to -60 knots. In your example, the aircraft also undergoes a change in momentum of 120 knots (times the aircraft mass), from 0 to -120 knots. From the point of view of the aerodynamics, there's no difference -- same momentum change, same force in both cases.