OK, they won't be arriving tomorrow, but somewhere between the X-Prize for automobiles and the X-Prize for private low-earth orbit private spacecraft, lies NASA and the CAFE Foundation challenge for "Comparative Aircraft Flight Efficiency."
Combine the quest for more efficient airframes and engines with new fuels and fuel types, with the explosion of UAVs across the mission spectrum and who knows what the hell airplanes, let alone ours and other air forces, are going to look like in a couple of decades.
One thing's for sure: it won't be a simple extrapolation beyond where we are today from where we've been. Using a 75kW electric motor using brushless technology, the all-electric lithium polymer powered plane pictured here just reached 250 KPH. Do you suppose future tankers, fueled with JP-8 or electricity, will dangle extension cords to re-charge power hungry manned and unmanned aircraft?