garymortimer writes "Air to air refuelling for UAS has been spoken about for years, a single system to service Predator, Darkstar and the Global Hawk was once sought. Now the X47 joins the party. Saber Tanker Aerial Group (STAG) are trying it in the civil area. Last year Cobham were chosen to support Global Hawk autonomous air to air refuelling trials. Bristol university is also part of the rush. Reliable tanking is all the rage.
Take off and landing are the most difficult part of any flight op, manned or unmanned.