Oleg, you'll be my hero forever if you can do this:

[Viikate]

Normal commercial AM radio station can be used for navigation just like non-directional beacons. But of course the pilots didn't listen Glenn Miller all the time as if they would have iPods.

For example mid-late war German single engine planes had mostly FUG 16Z radios. Z meaning zielflug (homing). There a ZF-FT switch to toggle between two modes. Zielflug or Funktelegraphie. So you either can tune to NDB/radio station frequency and us it for homing OR you can talk to your wingman or ground control. So obviously Hans is not listening Lili Marleen all the time.

Bombers normally have several radios (mediumwave, shortwave, etc.) Check Ju-88 or Bf-110 for example. They could have kept one channel open for communication between planes and tune another receiver to AM radio station and route the music through intercoms so that all members of crew can hear it. To relieve battle stress and uplift moods.