I had to do the same thing last year and left the shaft in the bag and when i got the out it was fine and i just put the head back on. I kept the head wrapped in a towel in with my socks in a hard shelled suitcase and it was also fine when i got it out. Hope this helps. Have fun on the trip.

thanks all for the replies they really help

I did exactly this and had no problem. Just remember to pack your surefit screw and hosel parts safely together.

The TSA agent scanning my carry-on luggage noticed they were the heads and suggested that I needed longer clubs ;).

Very interesting concept.  I have a travel hard case on wheels for my clubs and bag.  Of course I normally drive now and haven't used it since I went to Ireland.  It is well padded and have never had a problem. 

Pick up a club glove travel case with a stiff arm.  I traveled nearly every week and never had a problem.