|Hans, I think the version you posted is a tad too dark - see my crit.|
So I tried a little ws.
Using adjustment layers I:
- changed levels: 0, 1.4, 226. Goal: more light on the planes
- Shadows and highlights on bg layer: 0, +20. Goal: make the sky a tad darker again
- color balance: +15, 0, +15, adding a bit more red and blue.
- finally: sharpened a bit, USM +90%, 0,4, 0. More detail in the decals, but unfortunately, also a little halo around canopies and wings...