[quote=@Cyclone][@Willy Vereb] 

What, there are just bored nobles rich enough to have air squadrons? And it's not illegal for them to work for the crazy nations across the sea? Well, I suppose elven mercenaries it is!
[/quote]Nobles in my nation have the duty to defend their country and have the honor that depending on their status they can maintain a military force of a certain size.
This lead to nobles often creating "elite units" from the best stuff they can afford.
Also regulations on the use of this military force is kinda lax.
So yeah, just like you said. You can find bored nobles who have an entire squadron of planes and are willing to stay in your country for a "reasonable" prize.
The emperor may recall them or even issue punishment for such actions but generally it never happens unless they are preparing for a war of considerable scale.
You'd also have a hard time to convince these elven nobles to attack their own nation but attacking supposed allies or with whom Yllendthyr has friendly relations... everything for the right price.
:lol