To get the Khazam Airship pass you must do a few things.
First and foremost make sure that you have registered your Rise of the Zilart expansion. Many people (myself included) run into issues with this and wonder why they got the keys yet can't get the quest. Registering/Installing solves that issue.
In order to get the three keys you must goto each City's main "dungeon". Sandy O - Ghelsba, Bastok - Palborough Mines, Windurst - Giddeus.
Each area has 3 types of mobs (i've heard that there are more than this in certain area, but haven't heard it confirmed) that drop the keys.
Unfortunately i cannot remember all the specific names of the mobs, but if you have time please check the other forums (this topic has already been posted) or goto GameFaqs.
Hope this helps a bit :)
Oh and for the Original Poster (Harry):
Khazam worked wonderful for me. Like they said earlier, the area right outside Khazam (yohtunga jungle i think) is perfect for good XP chains (madragoras) and has your safety zone as well. I leveld up there from 26-30 in 2 days.