When I was trained in Aerospace Engineering at Texas A&M in the 1980s, we were taught to use what has been referred to as the Gravitational FPS system, where distance is measured in feet, force in pounds, and mass in slugs. This was a big disappointment to me at the time, since I had been quite comfortable with metric units in high school physics. However, at the time FPS still dominated the US engineering literature.
I remember that one semester we had a visiting lecturer in dynamics who was also continuing his work as an engineer at NASA (Johnson Space Center.) He announced to us early in his classes that he would only accept work in FPS, and not "those damned communist units."
When I got to NASA/JSC in 1984 I found that FPS was quite common in most of the Shuttle simulation code that I worked on (I never saw any actual flight code,) but metric units were also used by some teams, and if anyone harbored any political biases around systems of measurement, they kept it to themselves. In almost all cases, however, when data were presented to crew or (especially senior) engineers, they were converted from consistent units (whether SI or FPS) to feet, pounds, pounds-mass, nautical miles, knots, degrees (both Fahrenheit and angular,) and other "traditional" units.