"Actual controls engineers" use PD loops (no I) all the time.

In some circumstances, yes (usually when the system itself acts as an integrator somehow). Aircraft controls do not strike me as a system where this is sensible (trimming an aircraft is basically an integral control process).

(d'oh, should have read the specific context: in the case mentioned, it is where the system acts as an integrator (pitch -> altitude), and so pure P control is pretty reasonable)