ΔE 8.5, close: similar, with a visible difference side by side. USAF Brown is a little lighter, warmer than Us Olive Uniform.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). USAF Brown is a little lighter, warmer than Us Olive Uniform.
The same difference applies the other way round: Us Olive Uniform is a little darker, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Us Olive Uniform on the colour wheel See USAF Brown on the colour wheel
All matches: Us Olive Uniform equivalents · USAF Brown equivalents