>>5279532No, I didn't use any decals, everything you see on the model so far has all been airbrushed.
What I did was make a stencil using Tamiya masking tape and an x-acto blade. I carefully placed a strip of wide tamiya tape over the decal sheet, and using the x-acto blade I carved out the checkered pattern. Since I already painted the under-surface red, all I had to do was mask the red portion and then over-spray the unmasked squares with yellow.
Another way you can do this easily is to scan your decals with a printer scanner, and then re-print out the decals using regular printer paper. This will preserve the decals if you mess up and want to use the decals instead. pic related, currently cutting out the stenciling for the USAAF roundrels.