Flying in convoy would mean drones could cover longer distances and carry heavier loads 

The average drone can typically fly continuously for up to 30 minutes and can only transport items weighing up to 10 pounds

A collective aerial drone would be capable of transporting 'virtually any size, weight, or quantity of items' 

Amazon is developing technology that will allow a flock of drones to fly in convoy, allowing the machines to cover longer distances and carry heavier loads.

The company has been granted the patent for a a large and robust flying drone, which is  made up of several smaller drones.

The Amazon Technologies Inc. patent says that individual modules could detach from the collective drone body once they were no longer required, allowing them to operate independently to deliver smaller parcels.