Another point. NorthernSky, I think u misinterpreted something about autopilots here. If I'm not mistaken John wasn't talking about autopilots avoiding the stall, he was talking about the autopilots fly the aircraft. Autopilots trim for alpha, and that's a fact. Trimming for speed in a heavy airliner with a constantly changing CoG and possible Mach tuck due to center of pressure shifts above 0.615M (in a 737) would present serious problem as weight shifted etc. Trimming for alpha means that the autopilot is 'thinking ahead' of the aircraft, relying on actual performance rather than what's indicated on the speed tape which as John mentioned can have built in or pitot and static position errors leading to an incorrect reading, whereas an alpha reading would negate the need for an airspeed indicator at all! Most V speeds are alpha related... Vs0, Vs1, Vno, Vx, Vy, the list goes on. But it's safe to say that 'stalling speed' is a VERY dangerous choice of words to teach a student. Get a student to pull 3G's at 90 knots in a Cessna 150 and ask him to explain the flick roll and spin that follows if he's been taught about 'stalling speed'!