3d Prototyping has been is use for many years in the UAV field, both for checking aerodynamic efficiency (in the wind tunnel) and for checking the dimensional integrity of a part before the capital expenditure of tooling.
What is new this time is the 100% use of the technique to produce a UAV. Having experienced the plastics produced from 3d prototyping methods - I wonder if a new polymer has been developed which will be able to compete (strength / rigidity / weight) with structures made from composite moulding in epoxy / carbon / kevlar / nomex / balsa. Before anyone says about balsa, its used extensively in composite moulding techniques in conjunction with epoxy / carbon. Typically end grain balsa sandwiched to form an incredibly rigid sheet material which is very light. For example: I-Core Composites, LLC - Manufacturer of End Grain Balsa Composites
It’s all very well producing a structure which looks ok, but if it’s not strong and light then flight performance is going to be seriously compromised. UAV’s typically have wing loadings measured in gm/sq.cm not KG/sq.cm.
The problem many designers face is finding a construction method which will allow either the UAV to be used just once or many times, dependent on its designed mission profile. An example of a single use UAV (Skate) can be seen here
Aurora Flight Sciences - Key Products and Services - Skate UAS. Many single use UAV's are made from EPP foam injection mouldings.
If thinking of multiple missions think of things like Predator