ΔE 7.6, close: similar, with a visible difference side by side. Light Blue RLM65 is a little lighter, more muted, cooler than Light Feldgrau.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Light Blue RLM65 is a little lighter, more muted, cooler than Light Feldgrau.
The same difference applies the other way round: Light Feldgrau is a little darker, more saturated, 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 Light Feldgrau on the colour wheel See Light Blue RLM65 on the colour wheel
All matches: Light Feldgrau equivalents · Light Blue RLM65 equivalents