I originally planned to produce the entire image with planes built from a model kit. But it turned out that the details are not really high quality, so I decided to use the model kit planes only in the background. The front Bf 109 is an original WW 2 airplane. The little ones in the background are Spitfires Mk 16. You would not believe how much work they needed until they looked something close to real planes... 

 

The background photograph was shot from a B737 short before landing in Berlin-Tegel. A combination of contrast filters was necessary to raise up the dull colors and contrasts. All is done with Photoshop CC, I never use any Plugins.