iphone 4, verizon....i will keep it in airplane mode, and put on wifi....i will not be able to get texts or phone calls (except through what's up which runs on wi-fi and i can use facetime with wifi)...is this correct? i will be on a cruise and don't want to run the risk of crazy charges....now, the emails won't come through either? or if they do, how does this work? please be patient with me, i'm new...and over fifty!