[Loser]

Batteries would not return as much power for their weight as fuel would. Gasoline really is a wonderful fuel source: portable, easily obtained, efficient, relatively stable, and of a tolerable level of toxicity. It is not only fortunate that certain processes led to it's widespread abundance, it is essential for the industrial development of humanity.

GPS only returns 'facing' based on movement. Since the plane will not always move in the direction it's facing (wind), I suspect they also had a compass on there.