ΔE 12.2, fair: the same colour family, but not a straight swap. USAF Light Blue is more muted than French Blue.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). USAF Light Blue is more muted than French Blue.
The same difference applies the other way round: French Blue is more saturated.
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 French Blue on the colour wheel See USAF Light Blue on the colour wheel
All matches: French Blue equivalents · USAF Light Blue equivalents