I like what you have so far! I like this paint design the best personally:
Here's what changes I think would make it "pop"
Tail number located like this Lynden bird, Flag a smidge bigger and lower since the tail number won't be in the way
text wise, stack the company name in the black font on this bird:
centermass air
solutions
Space the lettering so the first or last letter is dressed up right up close to the rearmost cockpit lower window
all lettering in black, no mottos/globe/eagle/website
Drop tanks in red with black mounting pylon
Engine nacelles red bottom, black stripe centerline on the prop spinner heading straight back
I like the pinup girl idea
think you could substitute this centered below the rear cockpit window, about half the size of what you have now for the pinup girl?
what do you think?