I carry my gear from oz to europe a fair bit, no issues ever had so far. depending on the airlines policys which all all here........
www.airline-baggage-fees.com/sports/windsurfing-equipment/The wind there is not that variable so i think 5-6m sails and a floaty board is all ya need. Maybe just carry your rig and rent a board, cuts the weight down too.
Enjoy.