Crab In my opinion you have negative airspeed in the example you quote. I think the term into/downwind only applies when you are near to the ground and the wind can affect what you are doing ie landing/turning close to obstacles.
In all other modes of flight we don't modify how we fly due to the direction of the wind ie we cruise at a set speed irrespective of the wind direction. (ok I know we fly at Vne when into a strong wind but that is for fuel considerations not aerodynamic)
HF