The end game of aircraft is energy independent electric aircraft as detailed in our reports on energy independent electric vehicles and unmanned pure electric aircraft. Indeed, a European manned aircraft is being built to rise from the ground to the upper atmosphere on sunshine alone - even powering the space suite of the pilot.
In the USA, organisations such as CAFÉ and the Sustainable Aircraft Foundation progress the agenda with vertical takoff and landing VTOL and extremely short takeoff and landing ESTOL manned aircraft a major interest. However, these need so much power they will be late in exhibiting energy independence.
The enclosed SAS presentations show progress including many interim technologies.