As you know, once you unlock the modification for planes, you can choose from a number of preset ammo belts for your guns. Each belt has advantages and disadvantages, but often times there is a very limited variety of belts. I propose that the once the player unlocks the required modification for changing belts, they are allowed to not only choose from the existing preset belts, but also create their own custom ammo belts using any combination of existing shell types for that gun. Say I want a belt with extremely good armor pen, but not much else. I create a belt using only AP shells(if applicable to that gun). Maybe I want a combination of many shells that are usable for the gun: AP-I, HEFI-T, API-T, HE, HEI. Basically, custom aircraft ammo belts using historically accurate shell options, so no using made up shells that were never used for that gun, like HE shells on M2 50. cals. All this would entail IRL is the ground deciding not to put Incendiary rounds into my ground attacker that's about to go shoot at concrete pillboxes.