If you would designing a drone like the scan eagle but optimising for large cargo and distance what would be the benefit of not having to take off and land apart from infrastructure and landing gear. How does that actually change the design of the aircraft, for example is the design case for aircraft determined by the engine's maximum thrust and the lift of the wings relative to the takeoff weight. Then from there there the design is optimised to ensure that operates efficiently as possible at the right altitude. Therefore if you didn't have to worry about takeoff then you could decide specifically for its operation at its optimum altitude?