Great Project for Fixifying (tm) the ambient "airliners" which currently are represented using their military versions.
Step 1: Add P-8 Poseidon Skin for "737"
Step 2: Add a separate P-8 Poseidon using the 737 model
Step 3: Rework military bits on 737 model to convert it into a civilian 737-800
Step 4: Add a new 737-800 in, keeping the old one for legacy reasons
Step 5: Make old 737 not placable
Step 6-10: Do the same for the A330/A330MRTT