I actually had the same thing happen to me today. I have no answers for you. Left Charlotte (4g) to drive up to BFE Virginia (3g). When I get to Virginia I have NO data at all. Tried toggling airplane, battery pull and anything else I could think of.
Went to the Verizon store after work, they did the same things with no luck. Next step is replacement from what they say. Having bought it from Costco I have to go there to exchange it (assuming they have any in stock).
Did talk to a Verizon guy on the phone and he was saying there was already a firmware update scheduled for october. And I wasn't the first one to report the data issue, there was actually a note in the system about the issue, but no real solution. Hopefully something good comes of this, pretty irritating!
This started happening to me today when I left Columbia, SC (full 4G coverage) to go to work in my hometown (3G). The phone tried to switch over to 3G and failed. Airplane mode didn't fix it. What confuses me is that I was in my hometown this past Friday and Saturday to work and 3G was working fine...