Trajectory is the fourth piece of navigation: once motion accumulates, where does this course appear to be taking me? The crucial distinction is that a navigator reads trajectory rather than predicting fate — projecting present position and conditions forward, not foretelling an inevitable outcome.
Given present motion, this is where the course appears to lead — not, this future will happen.
This is where AI could genuinely help: if you keep allocating time this way, these capacities develop; this project is trending toward dependence on one institution; this resource pattern is becoming nonrenewable. Stated as projection rather than prophecy, that is extraordinarily useful — and it is why the model insists AI navigation preserve uncertainty and alternatives rather than collapsing a trajectory into a verdict. At field scale, the lag between a trajectory turning wrong and the course being corrected is course-correction latency. See Navigability.