The Gustav is looking very nice David - your interior colours look spot on - just how you'd imagine the inside of an aircraft in battle.
Let me divert you away from it again for a bit, because I have just had a 30 second google of WW2 music and I can report back from Wikipedia as a fully fledged expert...
The officially sanctioned music of the Reich was Beethoven, Bruckner, and Wagner - preferably conducted by Herbert von Karajan and sung by Hans Hotter. Here he is post-war unleashing some Wagner (I lasted about 2 minutes of the 14 - without being too much of a 'philistine' this made me want to listen to Me262 by BOC again...)
The most popular song in WW2 among all troops was of course Lili Marlene (much more palatable) but still not everyone's cup of Earl Grey. The post-war version is actually very emotional - she is clearly very touched singing it:
https://www.youtube.com/watch?v=qR-nGIJAaw4
Interestingly Lili Marlene was a poem written by a German-Jewish soldier during WW1. Lili Marlene was released in numerous languages and adopted by the Allies in Africa - where it was also an Africa Korps favourite. More evidence that the actual soldiers were tragically bonded more by their similarities than their differences.
In 1938 the Nazis passed a racist law banning Jazz - unless for scientific research purposes (I know there is legitimate 'Jazz research' but that is hideous). However, bizarrely the propaganda machine of Goebbels put out a mocking jazz band 'Charlie and his Orchestra' - which was played to The United Kingdom and The United States - the following comes with the health warning that it is Nazi propaganda - so listen for historical interest if you choose.
https://www.youtube.com/watch?v=cLkhRMBOtzk
The Brits had their share of 'rousing tunes' - which were of emotional and social importance:
'We'll meet again'
'There'll Always be an England'
'White Cliffs of Dover'
Vera Lynn, and Flanagan and Allen led the way - more 'Blitz Spirit' than out-and-out quality in my view.
But as is being shown on iModeler at the moment the winners were the Americans! My mother and father played these every Sunday lunch-time - even when I was a youngster some 30 years after the war: Johnny Mercer, Irving Berlin, The Andrews Sisters, Duke Ellington, Harry James, Jimmy Dorsey and course Glenn Miller. I never appreciated them then - do we ever enjoy our parents music as much as they do? In comparison and looking looking back they are the sound that represents that time.
However, there has to be an exception to the rule - and HJM was that in most ways - his love of Jazz went against the edicts of his Nazi masters. So in order to redress the balance a little here is Hans Joachim Marseille's favourite, 'Rumba Azul' from the 30's by Lecuona Cuban Boys, which was played from morning to night on the day he died. I reckon you could build a 109 to this stuff!