Cellphones on an aircraft will not work through the traditional networks due to the altitude and distance from the transceiver towers. Some airlines do offer the ability to utilise the satellite uplink (the same that is used by the corded phones you will find on some aircraft) to make calls via one's cellphone.
Smartphones can be tracked by the GPS systems that they carry, these systems work at altitudes up to 60,000ft (roughly twice the average cursing altitudes of commercial flights) and at speeds of up to 1,200mph (again roughly twice that of a commercial flight).
I am bold enough to say (with the evidence at hand) that there is something very wrong with the case of flight MH370 and I would be very surprised if the general public is ever told about what actually happened......