Say you build a vehicle, and then create multiple different versions with very minor modifications. These might be things such as different armament, color scheme, or sub-assemblies. Instead of changing these around manually in the designer before flight, maybe you opted to make saves, so you can use them in versus mode.
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Rather than spamming the database and/or crowding your aircraft roster with saves of what's basically the same vehicle, a convenient feature might be the ability to create "variants".
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When saving an aircraft in the designer, an option may be to "Save as Variant". This will allow you to add the vehicle to a sort of sub-list of another. It might be possible to completely rename the variants, or just add a prefix/suffix or short description (such as MyPlane1 - x2 500lb bomb).
Loading an aircraft with variants in the designer or Versus lobby might bring up a drop-down menu with a list of the different versions. A note from the creator might pop up when hovering your cursor over one of those variants (MyPlane1 with desert camo / MyPlane1 with 2 500lb bombs / etc) This could also allow players to share multiple versions of their vehicles (such as a P-38 with both Pacific and D-Day liveries available, or equipped with either drop-tanks or bombs) without having to make separate aircraft to download. It may also be possible for interested parties to get a preview of the different variants on the vehicle's download page.