is the relationship between flight speed and angle of attack the same at height as at sea-level?

Answer 1

The angle of attack is the same, as well as the stall speed.
As to the 'flight' speed, the 'indicated' airspeed will be the same, but the 'actual' airspeed will have to be calculated. And the 'ground' speed will be affected by winds, and since winds are sometimes different at different altitudes, then ground speed will be different.
Hope that helps...

Answer 2

Not exactly.

Higher up, less air, so more airspeed, as opposed to sea-level, max air, less air speed.

It's called "density altitude". In a desert region, the density altitude, due to heat coming off the ground, can be vastly different than what you'd expect for the same altitude elsewhere.

Answer 3

True airspeed...no.

A greater angle of attack in necessary at altitude to attain a constant true airspeed.

Indicated airspeeds vary considerably from true airspeeds at any given angle of attack at sea level and at altitude (or different density altitudes...for that matter.)

Answer 4

yes, I believe so