US Aviation in the sense of the "aero" part of aerospace is still very much US Customary Units. I don't have enough experience with the "space" part of aerospace to comment on that. We still use pounds of thrust, slug and pound masses, psi for pressures and so on for things related to turbines and engines and so on. Strangely, we use kelvins instead of Rankines but that's the only exception I can think of.

Edit: Note that this isn't to say that aerospace engineers prefer the US units or that we don't know how to use the metric system or anything, it's just how it is. In this particular field, it's just the accepted standard.

In Aviation there are nautical miles for ground distance, knots for speed and feet for altitude. But in US aviation there are also statute miles for airport visibility and feet for runway visibility.

Customary units are bigger mess than imperial vs. metric.

Nautical miles make some sense because they are consistent with the lat./long. coordinate system (60 miles = 1° lat). For the rest, I'm not sure.

Would it be 60 miles for 1° in all locations for the latitude, considering that the earth is an ellipsoid/spheroid?

Latitude is measured along a Great Circle of Longitude - confusing isn't it? So the distance between (say) 10 and 30 degrees North is the same as the distance between 50 and 70 degrees North.

The Latitude circles (in the 'horizontal' plane) get smaller as you go from Equator to the Poles, but all the Longitude Circles (in the 'vertical' plane') are all Great Circles and go through both the North and South Poles and so are all (pretty much) equal in size.

Iso fasteners and metrics blueprints are favored for all NATO activities, but it's not all military stuff. Moreover, a lot of iso hydraulics stuff is imperial.