ΔE 6.8, close: similar, with a visible difference side by side. USAF Light Gray is a little darker than Duck Egg Blue FS 35622.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). USAF Light Gray is a little darker than Duck Egg Blue FS 35622.
The same difference applies the other way round: Duck Egg Blue FS 35622 is a little lighter.
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 Duck Egg Blue FS 35622 on the colour wheel See USAF Light Gray on the colour wheel
All matches: Duck Egg Blue FS 35622 equivalents · USAF Light Gray equivalents