I wouldn't hand an unprotected dress (let along a wedding dress even if in a garment bag) to the FAs and ask them to hang it and not expect it to be damaged in some way. I would talk with the bridal shop and ask them the best way to pack it and even see if they would be willing to help with the packing. They will also probably want to find someone in Tel Aviv that can help with getting the dress ready to be worn once unpacked.