The best replacement for autopilot is wind vane.

The best alternatives to autopilot are rated as following:
★★★★★  wind vane
★★★★★  infusionsoft
★★★  flight director
★★★  cruise control
★★  whmcs
★★  ipilot
★  autopilot
★  user mode
  accuair
  fap turbo
  aweber
  raymarine
  garmin autopilot
  jobber
  kap 140 autopilot
  fapturbo
  simrad autopilot

Your alternative for autopilot is not listed? Suggest!
Speaking about autopilot, one probably shouldn't forget about flight director.

Other search terms related to autopilot and their ratings are:
★★★★★ flight director
★★★★ osd
You have in mind a companion for autopilot and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of autopilot in all years. Click on graph for more.
autopilot
wind vane
infusionsoft