A friend of mine ordered the Peter Pan ship from the catalog not more than 2 months ago. It wasn't in the catalog, but they still had a few in stock. Doesn't hurt to ask!
Snowglobes by their very nature tend to develop the air bubbles. I'm not sure how, but that water can slowly evaporate (sort of like out of my water bed -- I put 5 gallons in every two months, but there is no leak. Where does the water go?

)
To help minimize them, you must:
1) keep them away from heat sources (i.e., fireplaces and hot air vents)
2) keep them away from direct sunlight (for reason mentioned in #1, and to prevent your whole house from going up in flames -- you know what happens to sunlight through a magnifying glass...nuff said)
3) keep them away from intense cold (see SueEllen's post for one reason -- severe temperature fluxuation causes the water to expand and retract, releasing some of the oxygen molecules trapped in the water...), but the other reason is that the globe water can freeze. Talk about a mess!
Airbubbles are the reason most of the new snowglobes have some sort of little "hat" on them.
But they can be soooo pretty!
Jan