Forget the sat phones, waste of time and money ----
I have the InMarSat handset with bluetooth, and I have never had any problems with getting or making calls, both stationary, in my car or flying. I even had a plug plumbed into my new panel to accept it so I can talk using my headset.
I just open the antenna, pop it on the glare shield and away I go.
It does prefer to have a clear view towards the north, but other than that, it seems to work fine?!