Risk in airshipping of speakers - experiences?

I had some Montana SPX speakers shipped from CA to NY via airfreight. They were housed in the original wood crates (2" x 3" bracing with 1/2" partical board covering). The speakers were cushioned with packing material on all sides and set firmly in the container (fastened by screws). Aside from the cost of shipping it was a trouble free trip.
You should look into the damage policy of the airline you choose and maybe some form of insurance.

Why not ask a distributor in Europe who ships his speakers from the US. Ask them how they ship and if they encounter problems. I think air freight would be better than putting it on a container ship, but a distributor would know better.