Sidestick
Well, I need a sextant as much as anyone need a private GPS in a Boeing.
Mind you I have one.
As maritime and aviation goes you only need to correct for altitude and voila , you have an accurate position.
Very popular as sole navigation aid for the likes of Roald Amundsen Umberto Nobile et al.
Dependent on horizon indeed! And satellites, err , sun , moon or stars .
Hence some hefty debates of who did reached the Northpole by air.
We did! BTW.