The first air data system widely used on jet transport aircraft was KIFIS.
I provided this explanation on another forum due to a similar question...
Kollsman Integrated Flight Instrument System.
KIFIS was a totally pneumatically powered analogue instrument system, using gears, cogs etc...the only electrical power was to provide failure function indications and cross-reference data.
An entirely adequate system for early jet transports.
And, utterly reliable.
However, because of the KIFIS system, autopilots of the day were, well....just OK, nothing to write home about.
For example, the Collins AP105 autopilot system used on many early B707's was quite accurate in the heading/altitude-hold modes, ILS/VOR modes, less so.
In the latter case, intercept angles needed to be kept within 30 degrees (maximum) as otherwise on-course information/guideance would be highly suspect.
This will provide a general simplified view.