Flygen systems are generally seen as a main AWE possibility. On Rope-drive transmission discussion a potential advantage is the motionless rope in y or rotating configurations, avoiding a too fast wear that occurs when the rope transmits mechanical power.
Some interesting possibilities are on https://www.nasa.gov/sites/default/files/files/Moore_EternalFlight.pdf. See page 9, the Centrifugally Stiffened Rotor-wing (CSR), and also Roeseler’s prior art mentioned on https://groups.yahoo.com/neo/groups/AirborneWindEnergy/conversations/messages/20025.
Flygen systems are torque or stationary systems (IMHO) with 16/27 potential Betz limit, continuous power, and only one flight mode.