I have always used the decal ones. I put them on thin aluminum foil. I paint the back of the foil to match the color of the red on the decal. I then use gloss or flat sealer to seal the decal to the foil. RBF flags are made in two types. Plastic or cloth. The plastic type are a semi gloss and the cloth are flat.
Once sealed they can be positioned in any way without cracking or falling apart. They can also be weathered to simulate grease, oil or just dirt.
Berny
Phormer Phantom Phixer
On the bench
TF-102A Delta Dagger, 32nd FIS, 54-1370, 1/48 scale. Monogram Pro Modeler with C&H conversion.
Revell F-4E Phantom II 33rd TFW, 58th TFS, 69-260, 1/32 scale.
Tamiya F-4D Phantom II, 13th TFS, 66-8711, 1/32 scale. F-4 Phantom Group Build.