Discrepancy in lore (spoilers)

[Jandor]

Garlemald's last aerial invasion of Eorzea ended with the fleet being massacred by dragons and Midgardsormr personally destroying the flagship. Gaius himself said the cost was too high.

An outside force of magic flying space aliens fighting the Empire to a standstill at the cost of their own millennia old leaders body is probably the worst example you could come up with if you wanted to show that Alliance can successfully deal with airships on its own.

A: The alliance didn't do it.
B: It didn't push the Garleans back beyond where they started.
C: The cost was arguably just as high, if not higher, for the dragons.

Just to clarify, my criticism isn't that the Alliance can take out airships, it's that we're never shown, or even told, how we're doing it.
Air superiority is important, very important, and I want to know how we're handling that aspect of the war. I can fill in the gaps myself if I have to and come up with plausible enough explanations; dragonkiller support, dragoon boarding parties, rogues sabotaging them in dock, etc. but I consider it important enough that the story just kinda glossing over it annoys me.

[Vyrerus]

An outside force of magic flying space aliens fighting the Empire to a standstill at the cost of their own millennia old leaders body is probably the worst example

Within the context of the game world it isn't. The Garleans don't know that dragons are aliens, for one thing. For another, to them Eorzea is a frontier. Not only do they struggle to combat Primals without recent technological marvels, but the amount of resources they pooled into the Agrius was substantially high. They sent it in, fully expecting it to absolutely crush all opposition and raze Eorzea mostly to the ground. Instead, it's a scrap heap in the middle of a lake.

Also, aerial superiority doesn't mean as much in this world, as it does in ours. Case in point, flying Imperial dropships bombard you during the last segment of Keeper of the Lake. Not only are these bombardments non-lethal, we can anticipate where they land more precisely than the Garleans aiming them. Without a rapid fire bombardment, their normal air units can't even touch us.

Add to this, they tried the same trick twice. They built yet another dreadnaught, being a FF Empire, they are addicted to constructing them. It has been unable to leave Azys Lla for at least 15 months by my count from battle damage sustained from fighting ONE Primal.

So Garlean Dreadnaughts are O and 2 vs. Filthy Savage Magicks/Filthy Frontier Dragons. They're about to be O and 3.

To address your points directly:

A: Doesn't matter. Cost the Empire so much that they won't willingly commit that kind of force to Eorzea ever again, until the events of Stormblood.
B. It got rid of the mainstay in their military force, allowing the Alliance to engage them on somewhat even terms until Bahamut happened.
C. That's the Dragons' cost to bear, because they acted in accordance with the pact between Middy and Hydaelyn.

[Jandor]

snip.

Dragons and primals are the reason the Empire hasn't tried to push into Eorzea again, but given we're not using either of those in our armies they provide literally zero explanation for how we're forcing them back.

Dragons didn't help us at Ala Mhigo, we didn't have a primal backing us up in Ghimlyt Dark. Eorzean forces defeated Garlean airpower on their own but we're never told how.

[Vyrerus]

Dragons and primals are the reason the Empire hasn't tried to push into Eorzea again, but given we're not using either of those in our armies they provide literally zero explanation for how we're beating them now.

Dragons didn't help us at Ala Mhigo, we didn't have a primal backing us up in Ghimlyt Dark. Eorzean forces defeated Garlean airships on their own with zero in-game explanation how.

Our powers are substantial enough that we can, and we have dedicated mages and artillery for those occasions.

Shouldn't need a lot of explanation when there's literally cutscenes of the Xaela's flying on birds and down airships with axes and magic.

A cutscene of Hien riding a Yol cutting a sky armor out of the sky with one stroke of his katana.

We also have sidequests in Stormblood where the alliance takes Magitek and trains soldiers to use it.

[Jandor]

Our powers are substantial enough that we can, and we have dedicated mages and artillery for those occasions.

Shouldn't need a lot of explanation when there's literally cutscenes of the Xaela's flying on birds and down airships with axes and magic.

A cutscene of Hien riding a Yol cutting a sky armor out of the sky with one stroke of his katana.

Powerful groups of dedicated anti-air mages backed by artillery? That sounds cool, would have been nice to ever see that.

The Xaela tribes aren't deployed in Eorzea, and they don't fight any airships. They fight a force that as far as we can see consists entirely of the much much smaller Juggernauts, those things aren't that much bigger than a Yol.

Funny you mention that Hien cutscene too, that would be the cutscene where Eorzea is yet again failing when up against Garlean air power, and yet again have to be bailed out by someone else?

Seriously, what sort of absolute morons don't expect to face aerial units when sieging a city held by a faction known for air power? What an absolute clown show of a military campaign.

[LineageRazor]

Honestly, I'm with Jandor on this one. Garlean air superiority has been handled ridiculously badly, in-game. (Like most things Garlean, really, but for the sake of brevity I'll not get into that.) Back in the earliest days of 1.0, the first ads I even saw for the game featured ominous images of flying Garlean air units, striking home just how dangerous they were. Potentially a great set-up for an underdog victory - but really, you gotta show how the underdogs EARN that victory for it to really be satisfying!

It really wouldn't even be all that difficult. Even without resorting to Primals or dragons, the alliance has resources that could theoretically be used to check Garlean's air superiority. Ishgard's dragon killers are one example, certainly, but thaumaturges on airships could certainly work, as well. I'm guessing that the Ironworks could help out, as well; even if Cid is against producing weapons, he could provide other tools, from things a simple as personal flying machines to more complex items like jammers to disrupt the Garleans' electronics.

Maybe the Alliance has these things, maybe they don't, but the important thing is we never SEE this. Our big battle cutscenes are just about always on the ground, nary a gunship to be seen. The only times we DO see Garlean air is when we have something new specifically to counter it, like Ysayle's Shiva summon or Hien's Yol armada.

It's possible that the Garleans keep their expensive air units in reserve BECAUSE they know the Alliance can counter them, but this is purely speculation, and has no reference in-game. Just one of the gunships we saw at Castrum Meridanum would have savaged even a vastly numerically superior ground force. Air superiority is a complete and total game-changer when it comes to battlefield tactics, and it boggles the mind that the Garleans don't use it more. It shouldn't be up to us to find reasons why they aren't used.

[VargasVermillion]

Honestly, I'm with Jandor on this one. Garlean air superiority has been handled ridiculously badly, in-game. (Like most things Garlean, really, but for the sake of brevity I'll not get into that.) Back in the earliest days of 1.0, the first ads I even saw for the game featured ominous images of flying Garlean air units, striking home just how dangerous they were. Potentially a great set-up for an underdog victory - but really, you gotta show how the underdogs EARN that victory for it to really be satisfying!

It really wouldn't even be all that difficult. Even without resorting to Primals or dragons, the alliance has resources that could theoretically be used to check Garlean's air superiority. Ishgard's dragon killers are one example, certainly, but thaumaturges on airships could certainly work, as well. I'm guessing that the Ironworks could help out, as well; even if Cid is against producing weapons, he could provide other tools, from things a simple as personal flying machines to more complex items like jammers to disrupt the Garleans' electronics.

Maybe the Alliance has these things, maybe they don't, but the important thing is we never SEE this. Our big battle cutscenes are just about always on the ground, nary a gunship to be seen. The only times we DO see Garlean air is when we have something new specifically to counter it, like Ysayle's Shiva summon or Hien's Yol armada.

It's possible that the Garleans keep their expensive air units in reserve BECAUSE they know the Alliance can counter them, but this is purely speculation, and has no reference in-game. Just one of the gunships we saw at Castrum Meridanum would have savaged even a vastly numerically superior ground force. Air superiority is a complete and total game-changer when it comes to battlefield tactics, and it boggles the mind that the Garleans don't use it more. It shouldn't be up to us to find reasons why they aren't used.

tbf if you look around in the ghimlyt dungeon you can see at the start the alliance has large cannons set up likely to limit the airspace that garlemald has over the battlefield. Ishgard more or less gave the alliance a surface to air unit which they'd be quite good at since they spent 1000 years fighting dragons, many of which would be smaller and therefor harder targets to hit. Basically eorzeas answers to garlemalds air-fleet is very much implied, but also bad when you consider they do a pretty poor job of showing it without the player being observant to details.

[Cilia]

OK, a few things -

Garlemald's "air superiority" is typically showed through their use of super-dreadnoughts like the Agrius and Gration - but those have both been dealt with. Outside of those (impractically) massive vessels, it's reliant on smaller escort craft or personal flying machines, both of which can be (and have been) dealt with using relatively mundane means (magic and artillery fire).

The drawback of super-dreadnoughts is that they are expensive to build, maintain, and operate; case and point, after the Agrius was destroyed by Midgardsormr it took the Empire 20 years to build another airship of comparable size and firepower... and it got taken out of commission on its maiden voyage (shades of Bismarck, anyone?). As powerful as the Empire's magitek is, its main advantages lie in ease of use and speed - but once the rest of the world picked up on how to counter it, it's become much less effective.

Eorzea... yeah, as someone else pointed out to me the Alliance that fought the Empire at Cartenau, during Operation Archon, and at the Ghimlyt Dark are very different organizations that have gradually racked up experience in dealing with the Empire's weapons and tactics; further past Heavensward and Stormblood it's picked up two very powerful nations in terms of military (Ishgard and Ala Mhigo, respectively) and added their martial might to it, along with an alliance with the Domans for the push into Ghimlyt. Ishgard in particular is very well-versed in anti-air warfare, so the idea the Alliance of now (e.g. Ghimlyt Dark) couldn't stand up to the Empire is... not quite so strong. The VIIth had the Alliance dead to rights at Cartenau, but that was 5+ years and numerous battles ago.

(Yeah, forgetting the Empire's reliance on air power during Rhalgr's Beacon was pretty dumb, but it all worked out in the end, didn't it?)

That bit about how expensive it is to build, maintain, and operate dreadnoughts is why it rankles the IVth has one. I can believe they'd have one (though I find it perplexing we weren't informed of it beforehand, given we knew about the Gration well ahead of time), but just using the thing should be massively taxing and not at all something to be made into a diversion (as it's implied Gabranth knows Bozja is a lost cause and is just throwing resources there to keep them occupied while he solidifies a hold on Dalmasca). To a fighting force strapped for resources, an airship like that should be used for a last stand or just nonfunctional due to a lack of fuel...

[Brightamethyst]

While we don't see it much in game, the empire doesn't dominate the skies. Presumably they're not shooting themselves with all those anti-aircraft guns.

[Wyssahtyn]

While we don't see it much in game, the empire doesn't dominate the skies. Presumably they're not shooting themselves with all those anti-aircraft guns.

At Ghimlyt? I'd presume that's just there for aesthetics, unless we're assuming the Domans brought the Bird Force over with their teleporting vanguard. Eorzean airships are ill-suited for combat and not particularly maneuverable besides.