I make it with the Zeppelin Escort 

 But I lower the difficulty to Casual !
I set on the difficulty back to nightmare, but Ygerna was like "casual" as the Zeppelin Escort was as nightmare on Casual 

 ... pffff ....
The idea of escorting a Zeppelin is nice, really good idea, but I hope if such escort ever comes back a a next game, make it a little bit "
slower" ! It was fun to burn down Ballista's etc, but I haven't had the TIME to 
really enjoy this battle because it was a hurry, otherwise the Zeppelin goes down 
before he reach the place where it "successful" crashed into Ygerna's Fortress ... 
I am very enthousiastic about Flames of Vengeance, but please, next time make a End-battle in that way : 
the hero must/can combine human & dragon form in one area ... ! To find out when it's good to be in dragonform or when it's better in humanform it's all up to the gamer his/her strategical plan . 
On that way there's more posible to play it successful in 
different ways ! Each gamer has his/her own playstyle and via the Skills it's great to choose those skills that suits best ! 
For example : 
I'm a slow player, so skills as Stun Arrows, Polymorph, Chaarm, Blind, Hide in Shadows, etc.. give me MORE time to think about next move or run away 

 ) 
But during the Zeppelin Escort mission at the Black Ring Armada (great name, great looking place), 
I can't say I had the time ... to loose some "seconds" to fly a little back or whatever . I only concentrate on the Ballista's and use the Eye of the Patriarch on the bigger groups of Ballista's etc ... even on Casual difficulty !