Bird Man
Pre-takeoff checklist
This I think would be the best bet!
Me too, or over big towns. If I need to send a text message, I'll type it up, have it queued and ready to send. Hold the phone near the plexi window, and watch the signal strength bars as I get near a highway OR a town/city. Once I'm over either, I usually get 2-3 bars, send the message, and then put the phone away. You can check your incoming messages the same way, next highway or town.