They were not. Gyroscopes were used to maintain direction, and in the case of the V1, there was a timer on the fuel supply to set the range. This allowed London as a feasible target due to its size, but even for that the Germans were manipulated into aiming short be falsified news reports claiming that the missiles has overshot London.

This is probably why the proposed transatlantic weapon would have used s manned skip glider as a bomber to attack New York, not an unmanned missile.