MikeBanahan
If there is a conspiracy involving collaborators on the ground, it has already been pointed out that satellite phone contact would probably work from inside the plane, especially near a window. A small hand-held VHF set would be problematic and give very restricted reliable range of miles or tens of miles unless you were lucky.
I respectfully disagree - I've operated scanners on commercial aircraft and received VHF/UHF simplex @5W from hundreds of KM away. I understand that the aircraft implies some challenging RF attenuation characteristics, but it would be entirely possible to establish simplex VHF using a small dipole attached to the window of the flight deck.
I cannot, however, disagree with the fact that it would be possible to establish communications using a satellite phone from the flight deck.
There are a few choices of satellite phone providers: in a theoretical scenario where the person or people operating the aircraft after its disappearance communicate with ground crew using satellite technology, only a few providers become applicable:
Iridium: Iridium operate a large constellation of satellites in low earth orbit - if the parties in question used Iridium to communicate, it is highly likely that the phone was in visibility of multiple satellites. The number of satellites in the Iridium constellation would make it an excellent choice for someone who NEEDED comms with ground crew.
Thuraya: Thuraya operate a number of satellites in geosynchronous orbit, meaning that establishing a link from the flight deck window would require the satellite to be positioned correctly, or for the aircraft to be maneuvered into a position where line of site is achievable.
GlobalStar: GlobalStar has been plagued by network problems and have operational issues. They would be a poor choice for ground communications and anyone who needed communications for successful completion would be unlikely to choose GlobalStar.