Unfortunately all technically feasible but a long way from commercial.
Electric aircraft, bio-fuels and laminar flow new design aircraft all part of the distraction developed by the ICAO regulator and industry to ensure that no one notices the industry has no plan to transition off hydrocarbon fuel.
Despite the often chanted 2-3% of CO2 emissions the industry repeats, by mid century it will be substantively more.
Unlike the maritime industry, aviation has no plan to replace the present source of fuel.
- Electric aircraft are an exciting concept, but as Fullwings notes a transatlantic flight a long way away......
- Bio fuels are technically feasible, but the sheer landmass required to grow the fuel would result in less food growing areas. Of course, bio-fuel still produces CO2... As a point of interest to replace 10% of the US airlines ASK would necessitate an areas the size of Florida to grow the fuel.
- Laminar flow developments aside, the flying wing concept as depicted by ICAO would fly for sure, but the re-design of all the associated infrastructure to support this new design is very very costly...