editing loadouts?

[orca]

It is possible to add a weapon to an aircraft's loadout while the aircraft is in the air. However, after the aircraft lands and then readies, the loadout returns to the standard loadout without the edit.

Is there a way to maintain an edited loadout?

[SeaQueen]

Not without editing the database. If there's a specific loadout you're interested in, the team is generally pretty responsive to adding them, particularly if you can provide a photo of the aircraft with that loadout. With 5th gen aircraft and bombers that's sometimes hard to manage on account of internal bays, but generally if you're polite and can provide some documentation to support it, they're good.