Still used, sure, but not solely ( 'alone' ) - it's augmented by GPS height, feedback from ground radar, onboard radar facing down and forward, etc. See: https

Still used, sure, but not solely ( 'alone' ) - it's augmented by GPS height, feedback from ground radar, onboard radar facing down and forward, etc. See: https://en.wikipedia.org/wiki/Altimeter https://en.wikipedia.org/wiki/Altimeter that list five types (including trad. air pressure type)