Well, as we all know, Belthasar designed the Blackbird. But he didn't actually build it. In fact, it was Dalton who oversaw the construction of the Blackbird in 12,000 BC, which means he had the blueprints.
Now then, I wondered; perhaps Dalton engineered a second Blackbird after the first one fell? Perhaps he used it against Guardia.
It's yet another thing to explain how Porre won over Guardia. We already noted the elements of El Nido, Dragonian artifacts, maybe the Sun Stone, and other stuff. But perhaps he also constructed a new Blackbird in Porre.
It's a long shot, but hey it's possible right?