ΔE 13.9, fair: the same colour family, but not a straight swap. USAF Light Blue is a little darker, cooler than Bluebird Grey.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). USAF Light Blue is a little darker, cooler than Bluebird Grey.
The same difference applies the other way round: Bluebird Grey is a little lighter, warmer.
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 Bluebird Grey on the colour wheel See USAF Light Blue on the colour wheel
All matches: Bluebird Grey equivalents · USAF Light Blue equivalents