We use SAE for consistency through the years, not because they are 50y behind. Also because it's much more regulated then the car industry. No reason to change the fasteners that work for another system, especially if you have to go through testing again. But some modern aircraft do use metric.
I've never seem any torx in aircraft fyi, but I've also haven't worked many models anyway.
They are new to me.
I see them on newer commercial airliners and some defense and space products.
Maintainers like them because you can transfer a good amount of torque thru them without slipping, stripping the head.
Maintainers don’t like them when their recesses get filled with paint or aero filler. Picking paint out of a Torx recess *****.
We’ve had some problems with heads shearing off on the smaller sizes where the Torx recess is larger (and deeper) proportionally to the head, such that there’s not much meat left at the bottom of the flush head.
Otherwise, saying aerospace is “behind” automotive because we’re still using SAE hardware or using “old fashioned” heads is a bit uninformed. We are a decade or more ahead of automotive in our use of materials, analysis methodologies, and general vehicle technology, especially autonomy. I guarantee stuff we’ve been working on in the last 10 yrs will start showing up in passenger cars soon.
Automotive is ahead on some steel finishing, and manufacturing’s use of automation on final assembly, but we’re catching up. And our robots do more than automotive robots do. We ask more of them.