We use Thurya handheld Satphones at work in remote areas, and they generally work OK anywhere. They will also pick up a cellphone network when it exists. Dont expect western landline quality though, still a bit of delay sometimes and some "can you hear me....etc". Never tried one in flight, though they work fine speeding across the desert in Landcruisers, they dont always need to have a clear view of the sky.
Regards, SD..