The square-cube law implies some performance characteristics that only big-enough craft can fulfill, and at that size point you aren't saving money with "disposable" cheap-and-small drones. Specifically, air resistance scales with cross sectional area, while fuel storage and engine power output scales with volume. You can trade off fuel for engine power by making a more missile-like design, but then you're left with a conventional plane.
Like, this is the fundamental reason why ground-based missiles don't rule the skies. Aircraft can go high enough and travel fast enough that any intercept solution has you firing well before they've committed to flying into the effective range of the missile.
But wouldn't there still be a lot of savings for not having a human and all the controls that come with it - and maybe some more flexibility in design?
It sounds like they are looking for air-to-air replacement?
Not caring bombs saves a lot of weight and size.
Hell maybe even just do what terrorists have learned and make cheap kamikaze drones which are really fast and simply blow up.
Like, this is the fundamental reason why ground-based missiles don't rule the skies. Aircraft can go high enough and travel fast enough that any intercept solution has you firing well before they've committed to flying into the effective range of the missile.