From your keyboard to god's ears, I hope.
I'll see if I can figure out how to implement it like that in my modmod.
I'm planning a few of these too. The basic birds will remain the same (expect just being called "bird," "tamed bird," or "trained bird" instead of hawk, since some are parrots or ravens), but I'll probably add 2 new levels that can attack. I'll probably let them get promotions, and in fact have a level requirement for the top level bird.
I'm also thinking that I'll add a "Rok's Nest" unique feature that that can only occur on a peak, which would spawn a
Greak Roc -- a powerful unitcombat_beast, domain_air, specialunit_bird barbarian hero which would harass units within its large range. (It is a good thing that Beastmasters can move impassible

)
I'm also going to look into allowing birds to rebase the way they could in vanilla civ.
I'd also like to see dragons and other ground+flight units to be able to recon, causing 1tile damage, 9tile damage no damage or cast a spell - at recon mission destination - by choice. After you do the recon mission, the spell/ability the unit casts takes affect as if the unit is in the recon missioned tile. Now that's range spells. Give me flying mages casting at recon mission destination and I bet archers having a little range damage is no big deal. I wish to swooop in and cast terrible things! Flying I - IV promo. Levitate (air 2) gives Flying I, Swooping (air 3) gives Flying II (+1 for each of caster's spell extension promotions). Flying I - IV determines range.
Who doesn't want to fly around casting stuff at range?!
Your references to "recon mission attacks" seems a bit odd, but I think I know what you mean. It wouldn't actually be recon, but something more like air combat. I've already given archers/siege/some ships ranged attacks, through the AirCombat tags. It works quite nicely, but it doesn't move the unit to that tile after attacking. The AI is already very good at using such ranged attacks, although it doesn't prioritize building them very much. (I think this is because Kael lowered their weighting since melee units are usually better in FfH)
I recently discovered (when I was trying to let Profanes act as nukes) that giving normal land units a <iNukeRange> value doesn't make them explode and cause fallout; instead it works
a lot like you suggested flying attacks should. You move to the distant tile if there are no more enemy units there, and otherwise stay where you were. (You can capture slaves from a distance too, but I haven't yet tested whether </PythonPostCombatLost> or <PythonPostCombatWon> work this way.) It does still cause the whole map to shake violently though, so I think that method would only be appropriate for really powerful units, like Dragons.
I was planning to change breathe fire (which summons a meteor) to a more appropriate spell that works like Pillar of Fire, but where the Damage type depends on which dragon it is (Drifa should do Cold, not Fire). I have considered instead giving them ranged attacks (I was thinking it would AirCombat like I gave archers, but the Nuke route is so much cooler.

), but always ran into one problem: Acheron would never be able to attack, as he has 0 movement. I find is really annoying. Would people mind if I allowed Acheron to move (and make him, and all the dragons, much stronger), but made him more expensive so that he won't show up until at least midgame
I'm sure that the code used for recon missions, paradropping, air combat, and nukes could be borrowed for use in ranged/targeted spells, although that is still above my coding skill at the moment. (Since the AI is good at targeting ranged attacks, why shouldn't we be able to borrow that code to make it good at targeting spells?)
I have been suggesting that it be revamped like this for a long time. (Actually, I think I may have first suggested it while targeted spells were still present, since I thought that moving targeting to the SDK would make the game faster, more stable, and easier on the AI. Also, these ranges mimic the radius of a circle like a fat cross does instead of giving the unsightly square range.)
Promotions already have the ability to increase aircombat range, so (if this were borrowed for targeted spells) it would not be hard to let Spell Extension increase the range of targeted spells.