Stratospheric Flight Aeronautics at The Limit

The stratosphere is the highest layer of Earth's atmosphere where aircraft can still fly. The density of the air is just high enough here to generate lift on a wing or buoyancy on a balloon, so designing any stratospheric aircraft is a delicate technological balancing act for the engineer. Designing and operating an aircraft capable of conveying humans to the stratosphere is more challenging still: biologically, we simply do not belong up there.