I think the implication is that you're travelling into the centre of Damian's territory so any path you clear would simply be closed up by his overwhelming numbers which may as well be an infinitely large horde; the path you take is most likely the most vulnerable to his forces. But I admit it isn't depicted that way.
I think the aerial battles are one of the game's few weaknesses: I feel weak and vulnerable as a dragon compared to being in human form, and the Zeppelins seem ridiculously fragile given that they're actually extremely heavily armed flying gunboats. It could be the case that however seriously lethal they are otherwise, they still fulfil basically civil duties as their job is to transport goods and people as much as it is to patrol whereas a warmonger like Damian instead pours his entire efforts into going on the offensive so his fortresses are going to outgun it no matter what, but again the depiction seems to be more on the vulnerability of the Zeps, not helped by them even being brought down by goblins who seem to be more of an irritation than a credible threat.
That aside, the cinematics of the opening part of that section were very impressive with the Zeps emerging from Aleroth's aerial "ports", and confirmation (well, reminder, but I'd utterly forgotten) that the thing about Champion Harbour is in fact a viaduct-of-sorts through the mountains to get to Aleroth: the cutscene after Farglow went through the deeper part of the fjords as Farglow's obviously a diversion from the usual route.
Also interesting that the "shipyards" where they're made is in Rivertown: as a town with no rivers (! As it was shown in DD) obviously they would have a vested interest in alternative modes of transport, necessity being the mother of invention and all that.
I'll likely have a few other sweary attempts to escort the Zep. Reading the online guides, other suggestions were to use F11 to turn off cooldown times so if that applies to the Zep as well I can just get it to blast its own way through. Not sure if lowering difficulty will help as it's not clear whether it only lowers the damage and armour of enemies or if it's all non-player characters.
