b82rez said:Each aircraft manufacturer sets the minimum altitude you can use the AP after takeoff...somewhere around 500 to 1000 feet.
You can use the AP whenever you want, with or without the autothrottles.
You can use the autothrottles whenever you want (takeoff too), with or without the AP.
Also depends on the airline. I've flown the A320 for three different airlines, each airline had a different minimum for autopilot on and off (autoland).
Depends on the Ops Specs for each individual airline.
Depending on the aircraft, autothrust may be used in all aspects of flight.