why fix what aint broke? Aerospace bolts and nuts are orders of magnitudes more regulation stringent than automobiles. And it really isn't just as simple as changing bolts and nuts... Basically the entire plane has to be created again. Every single blueprint with a new hole/countersink needs to be updated. Every subcontractor and emergency repair facility needs to have their legacy mylar drawings updated.

All for what? Getting off inch system because it's "illogical" for a select group?

And unfortunately, doing work costs money.

If there's a story I want to hear, is one of how automobile companies transitioned into Metric. I'd imagine it's not too difficult since they come up with a new vehicle platform every couple years.