KB9JMQ said:
BTW I can't remember their name but I once used a group of flying humanoids who hold bows with their feet to attack an airship once. It was a pretty good battle.
Maarashi, I think...but I'm not sure. And I can't remember the source, for the life of me.
As for weird cargo, how about something with troll parts - ie, since the largest part of a dead troll regenerates into the troll, have a couple cargo containers marked "Regeneratives" on board at the behest of whoever is staging this (or one of the groups staging something). Each has a chunk of troll which is slowly growing back to full size. The arcane-biologist mad scientists whired to craft the "Troll Bombs" have figured their regen rate to a fairly precise point, at which point, starved and cramped, they break out of their containers. Which, as a note are permanently silenced so no one gets suspicious of the roaring.
Also, as a red herring, you could have an individual or group who has a bone to pick with your PCs (there seem to be a few in the Storyhour) who don't have an agenda against Breland, they just want to frame/hurt the rep/maim or kill the PCs for past indignities. Meanwhile someone has political motives, this group, like an influential backer or supplier of the gladitorial contests in Sharn, is just out to blacken the eyes of the Guardian Angels. This may trigger before, during, or after the "real" kidnapping/murder attempt. This gives an option for one or other of the plots to allow the PCs to think they've got past the "rough spot" of the voyage, only to have the other group strike.
Having 3 or 4 groups all fighting each other for victory on the airship (whatever victory means to them) can also be something of a hoot, as alliances change from round to round as the PCs and various "villains" work together to play "keep away" from whoever is going to do something to or with Haydith that will ruin someone elses plans:
Group 1: Wants to Kidnap for Ransom
Group 2: Wants to Kidnap for Love
Group 3: Wants to Murder for political reasons
Group 4: Wants to protect the princess to gain royal favor (hired group 3 to kill her to make sure would have an opportunity to protect her) to gain court access to kill other monarchical targets
Group 5: Mars needs Women (A cross dimensional Githyanki voidjammer looking for breeding stock appears and want to enslave the women)
Group 6: Wants princess to live, but be infected with a subtle disease, parasite, magical effect to be triggered at a later date
Group 7: Wants to do things throughout voyage to ruin rep of Angels, possibly permanently hurt or kill them, or foil their task for completely personal reasons