This paper summarizes the results of a study on the design of high altitude long endurance (HALE) unmanned aerial vehicles (TJAVs). A review of previous designs revealed that most were point- designs rather than general purpose vehicles, leading to cost inefficiencies. It was therefore determined that efforts should be made to design HALE UAVs that are capable of performing a wide variety of missions. Additionally, it is desirable for these vehicles to be as inexpensive as possible, in order to allow their use by a wider base of customers. In the present study, a family of three mission-configurable HALE vehicles has been designed. Between them, these vehicles span the majority of the payload/endurance requirements of previous designs. In addition, through the use of common parts and subassemblies among the three craft, it is shown that vehicle unit cost can be reduced substantially; perhaps by as much as 25%.