Primering started
Before primer the entire plane, I temporarely applied the canopy.
The provided masks are indeed, like mentioned by Tom @tom-bebout, not usable on curve surfaces. On the cardoor windows they worked fine, but they didn't stick on the canopy. Therefore I now simply use masking tape.
First the interior color was applied on the canopy and doors, followed by the first two layers of primer.
Once dried, the surface will be checked for required corrections.