There are several systems that can be installed on aircraft, from corporate to commercial, that allow the use of mobile phones. There are several Airbus SB's for GSM on board systems for example (called OMTS). I know this as we have it installed on our aircraft (A319)
These systems install a pico cell on the 'plane that effectively vastly reduces the phones power output so that interference is less likely. The installation of these systems also requires an EMI check following installation to ensure no unexpected interference occurs.
The system works worldwide, except in the airspace of those countries where the regulatory authorities do not allow its use. In which case the on board pico cell shuts down and mobile phone signs illuminate.
I have it on good authority (the system provider) that in the vast majority of airspace where the system cannot be used (the USA is a notable exception) the reasons are financial and not due to safety concerns. In a nutshell the ground based regulators want a slice of the cake for allowing use of mobile phones in their airspace.
As has been stated before, the original thread has nothing to do with the use of 'phones on board aircraft, but refers to hacking into ground/air datalinks or interfering with navigation signals which could be done from anywhere and would require quite a bit more than a mobile phone 'app'.