I'm deploying in September and I plan on my wife and I both having iPhone 4's. Currently she's is 38wks pregnant. When I leave my daughter will be around 3 months old. I won't have cell service over there but I'm sure I'll find wifi. I know facetime says wifi only, but do I have to have cell service to initiate it? Will it work while my iPhone 4 is in airplane mode? Thanks for the help!