A new mobile network system could make the latter method much more reliable.

Although it's certainly possible that drones might simply lack network coverage at various points along their journey, it is also believed that because the aircraft are able to access multiple cell towers simultaneously, they keep switching between network cells – doing so leads to frequent disconnections.

Additionally, scientists at Germany's Fraunhofer Institute for Telecommunications have discovered that the communications protocols which regulate the flow of cellular data between drones and their operators can be problematic.

With these limitations in mind, Fraunhofer teamed up with partners including German drone manufacturers Wingcopter and Emqopter to develop what is known as the SUCOM network.

It reportedly allows drones to stay connected with their operators via cellular networks, even if data rates fluctuate. This means that important real-time information such as flight direction, altitude, speed and GPS coordinates are continuously available.

"For comparison, we equipped a drone with a commercially available LTE system and with our SUCOM mobile network module, which has the new communication protocols," said Fraunhofer scientist Tom Piechotta. "While the connection that used the conventional module kept dropping out, the SUCOM module provided a stable connection. Thanks to our new protocols, the connection is so stable that there are no interruptions."