The Missing Airliner quest begins at the end of the Prologue, and will carry through to the City of Bose. There is actually so much to this quest that it is broken up into two parts!

Client: Mayor Maybelle
Pay: 6000 Mira, 5 BP
Bonus: Up to 3 BP
Details: Direct Request
Difficulty: Hard
Locations: City of Bose, Haken Gate, Abandoned Mine
Description:

Part 1: The airliner on which Dad was riding disappeared over the Bose region... so we set off to the area with Schera to see if we could ascertain what actually happened.
It seems the mayor of Bose City has requested an investigation into the incident. Let's have a chat with her!

Part 2: It seems someone in Ravennue Village o the northwest witnessed a large flying object in the sky on the night of the incident.
The miliary unit sent to investigate the claim came up empty-handed, but they may have missed something. It's worth a look!

1. Bose is west of Rolent, across Verte Bridge on Milch Main Road.
2. We got through, but re-entry to Rolent is not permitted...
3. The mayor's house is on the west side of town. Let's go!
4. The mayor has gone to the chapel.
5. Ran into her maid. Seems the mayor let for the market.
6. The mayor's request is to look into and resolve the matter.
7. Got a letter to General Morgan.
8. He can be found at Haken Gate, located along East Bose Highway.
9. General Morgan is out. We'll await his return at the fort.
10. Met with the general! Seems the Capua family demanded a ransom.
11. Let's report back!
12. Reported our findings! But sadly, there are no further leads...
13. Could the reporter, Nial, have gotten a scoop? Let's find out!
14. Ravennue Village is on the north end of the West Bose Highway.
15. We arrived in Ravennue Village. Let's speak with the elder first.
16. The witness is a boy named Lewey.
17. According to his statement, the flying object was headed north.
18. Let's head out the back, and scour the north trail for clues!
19. Found the entrance to an old abandoned mine, but it's locked.
20. Maybe the elder can get us in...
21. Borrowed Abandoned Mine Key!
22. Use the key, and got in!
23. Found the airliner!
24. We almost got the sky bandits, but they gave us the slip again!
25. There was no sign of any passengers or cargo from the Linde.
26. Let's just head back to the guild and contact the Royal Army.
27. We were mistakenly taken into custody by the Royal Army...

After learning about Cassius' fate, say your goodbyes to everyone in Rolent and complete any outstanding side quests, then head west via Milch Main Road to Verte Bridge. You will need to speak to CWO Ashton about passing through the gate. You will be warned in the game, but, just to make sure you understand, I will tell you, too. Once you exit the other side of Verte Bridge into East Bose Highway, you will be unable to return to the Rolent side.

As long as you stick to the main path, it isn't too difficult to find your way to the City of Bose. Compare to the City of Rolent, Bose is a bit larger to navigate and contains a large market area at its center. Your first location of interest is the Bose Bracer Guild located north of the market. After reporting in, and making everything official, head to the Mayor's Residence, located west of the market, only to be led on a small tour of the city to find her. After checking the Chapel, you'll finally catch up to her in the Market.

After a short discussion, she will give you a letter to present to General Morgan, who is in charge of Haken Gate. Complete your side quests, then head over to Haken Gate via East Bose Highway and Eisen Road. You will find yourself talking to many NPCs at Haken Gate, especially at the bar area, before the general will see you. A certain flamboyant character will stand out the most, who becomes very important later. To progress the story, talk to the sentry at the east door, then visit the bar on the east side, and wait until you're summoned to see the General. After speaking to the General, head back to Bose and report your status to the Bracer Guild and to Maybelle.

The second part of this mission begins after speaking with Nial, who is found at Kirsche's Bar during this part of the story. During this cutscene, he will tip you off that there may be a witness in Ravennue Village that should be interviewed. If you've done the side quests already, you probably already have an idea who it is, but you'll be forced to follow the required steps regardless. Take the West Bose Highway out of Bose, then head north on the Ravennue Trail. Upon arriving at Ravennue Village, you will be told you should seek out the elder. Elder Reisen is found in the large house in the northern area of the village. From there, seek out the boy Lewey, who is out sulking at the dock south of the Orchard.

After hearing the boy's tale, take the northern exit out of town to return to the Ravennue Trail. Take the western path, then north to the Abandoned Mine. You will find it is locked, so you will need to walk all the way back to the village, speak with the elder again, then walk all the way back to the mine. Yeah, not very fond of that, but it gives you a chance to farm the enemies here for experience if you are low.

Once inside the mine, you will find it to be full of Murder Crabs, who are very weak to magic. There aren't many here, so don't feel bad for casting some area effect arts to make short work of them. The path you are looking for is to the west, then north. Once you leave the mine, a cutscene will play out, which leads into the boss battle.

Much like the last time you encountered the Capua Family, you will fight a Capua and a bunch Sky Bandits. This time it is Kyle Capua, who very fond of grenades. The others aren't very strong at all, so I would recommend you to focus your attacks on Kyle, or hit the group with area attacks, then worry about the weaker enemies after.

Once the fight is over, board the Linde and seek out the many areas of the ship for clues. Particularly the Forklift at the entrance, the Generator Room, the seats on the bridge, the observation window and the plant on the 3rd deck. Upon entering the upper deck, with all the checks done, you will be asked your opinion on what happened, which will affect your bonus Bracer Points for the mission. For the maximum points, choose 'Ditch the Linde, because their hideout is somewhere weird'. You can now exit the airship for another cutscene that will take out through to the end of this quest. After you're back at Bose, be sure to report in at the Bracer Guild to complete it.