Since balloon wind data (direction and speed) is gathered by radar, it is ground speed/direction being measured - yes?

So the higher the altitude, the lower atmospheric density means less effect on your aircraft?

 

Thanks,

N99WB

Not sure what you're trying to ask here.

 

If the wind at your flight altitude originates from the front, it will slow you down and vice versa.

This is modeled in FSX, albeit most third party weather tools use an interpolation algorithm to determine winds aloft due to a lack of coherent source data.

So the higher the altitude, the lower atmospheric density means less effect on your aircraft?

 

Nope!  Just like Bjoern stated,  the winds aloft will greatly affect your aircraft.  If you are flying in the U.S., for instance,

try flying up in the jetstream either east to west or west to east and check on your ground speed.  You should be flying

at MACH when at those altitudes so don't pay too much attention to your KIAS.

OK, Thanks!