I need help, autopilot don't work, when I press alt + a nothing happen. I play the french version of the game and I use DOSBox 0.74-3

It's probably too late for the OP, but if someone else has the same problem, here a possible cause:

I am using a HOTAS to play the game and mapped the thruster to the A key to accellerate if it's in the corresponding position. And since having the thruster pushed forwards simulates a pressed A key to the game, activating the auto pilot by pressing Alt + A doesn't work (since A is already pressed). I need to get off the acceleration, and then i can activate the auto pilot just fine.