My six level 4 PCs have a flying ship.
What are some fun wandering monster-type encounters should they encounter? It's for a flying jungle and desert continent that has lost civilizations ruled by aberration-worshiping cultists, serpent folk cultists, rakshasa and other cat folk, ape and beastmen, gnoll and ghoul-land, and a fallen orc nation.
Monsters, storms, other flying ships, etc. They already fought a pair of manticores after talking to them (yuck!) and a flight of demon monkeys riding pterodactyls.
I'll start.
1. Half-dragon griffons
2. A thunderstorm filled with will-o'-wisps
3. A rival sky pirate ship
4. A drunk kirin
5. Vengeful manticores
6. Kraken-o'-the-sky
7. A mechanical problem
8. Problematic mechanical emancipationists (PCs from steampunk city)
9. Cloud behemoths (advanced floating dire hippopotami)
10. Ghost ship
11. Stowaway goblins
12. An ash cloud from an erupting volcano
13. A castle or army whose weapons all erupt at once (they're celebrating a wedding, but it's not immediately obvious.)
14. A migrating flock of clawbats
15. Haunted clouds
16. A cloud giant castle on a cloud
17. A haunted cloud giant castle on a cloud
18. Fey riding a roc who want to challenge them to a race. Expect very dirty tactics, especially if they refuse.
19. A forest fire threatening a village. Are the PCs going to be any kind of heroes?
20. A pair of dragons who are mating or fighting (hard to tell) and are throwing around scary magic, breath weapons etc.
21. A swarm of Vexgit Gremlins has found their way onto the ship and are halfway through removing the engine/releasing the dirigible when they're discovered.
22. The latest creation of Gnomeworks Inc., the Cloudcrusher 9000, is reported to be the pinnacle of all aeronautic aviation, equipped with the loudest, fastest and most explosive prototype of their Hellfire engine. Unfortunately, its maiden test flight puts it on a collision course with the group's airship, and the test pilot just pressed the big red button.
23. Against all rules of nature, a beanstalk ascends into the clouds nearby, a young boy desperately trying to escape a giant pursuing him down its length.
24. The mighty wizard Obrek the Turgid’s Magnificent Tower of Distended Repose floats high in the sky, far away from the noise and annoyance of the commoners below. He highly values his privacy, and your airship just buzzed his bedroom.
25. Mile High Moss, an extremely potent and valuable aphrodisiac, only grows naturally in small chains of delicate fronds suspended by highly flammable gas bladders in calm pockets of air high above ground. A skilled harvester could make a tidy profit from gathering this herb, though various cities have outlawed its possession.
26. Dire Crow Mob
27. Barrage of rocks falling upward. They can be knocked away or they reverse course if heated enough
28. Bubbles from a giant's bubble bath. Popped bubbles apply AOE blind, grease effect, moderate displacement, and the most curious odor
29. Oma pod mid migration
30. Flying monkeys, a tornado, and the most peculiar looking house
31. A horde of giant locusts/ locust swarm who consider an airships wood and fabric to be a tasty meal.
32. An old fashioned super storm that threatens to knock them overboard, or incinerate them with lightning.
33. A dwarven expedition is trapped on a mountain peak, between deadly sharp mountain tips.
34. A strange mold has been growing on the bottom of the ships hull and has eaten through/grown over the side and threatens the crew.
35. While moored on the ground a nausea of Goblin filth slingers have come aboard seeking any written words to purge, and any shinies to steal.
36. A local King demands property taxes be paid for "Air Land" being used in his kingdom without permission.
37. A magical part has failed, and the only gnome capable of fixing it has some very curious demands before he even looks at it. (Notorious for collections, pranks, and seeking the unusual should help with ideas).
38. A reverse gravity spell using wizard has fallen aboard (landed on the bottom hull), and is wreaking havoc with his cantrips and reverse gravity.
39. A very rare bird has nested atop the airship balloons, and is slowly damaging them, but is too rare/valuable/dangerous(fire attack of some kind) to simply kill/remove.
40. The party crashes into a rainbow, dazzling, blinding, and disorienting them while the angry leprechaun owner comes aboard to defend his treasure.
Best flying encounter is the one where everyone lands and fights on land.