Backward Blade, your analogy makes absolutely no sense because you justify your argument with a silly analogy. Of course mechanics are essential to safety of flight! Were you in the bushes for 3 weeks and a rock star came along with a bottle of water, you might decide that Rock Stars were more essential yet. Give us all a break, OK?
A true "engineer" is a design expert who can create a new machine. A "mechanic-engineer" knows the maintenance manual, obtains the parts and fixes the machine. If the mechanic-engineer does not follow the maintenance manual, he will go to jail (it happens too often). In sharp contrast, the true "engineer" wrote the maintenance manual.
Call your mechanic whatever you wish (especially if he gets very huffy and you need him to tighten bits in the bushes), kiss him on the lips because you love him, but he is a mechanic. Send him to engineering college and he might make a very very good engineer (perhaps better than those graduate engineers who don't know a wrench from a wench).
If you insist on using the same title for vastly different occupations with vastly different intellectual and educational requirements, then why not call your mechanic "Prime Minister", or "Doctor" or perhaps "Emperor of the Earth"?