Until this puppy evolves into a much bigger dog capable of carrying 10-20 tons of weapons 2,500+ miles, we're going to need fuel to keep our larger flying machines in the air. For energy and financial security, it means figuring out how to use less fuel and/or how to use a different fuel.
Let's table the Coal-to-Fuel discussion for minute, as it remains unclear how much overall utility the early attempts at this approach provide at present. Since the US has huge coal reserves, I agree CTF is a win for energy security, though we'd have to build a heck of a lot of news plants to scale up to current AF demand levels. However, a true home run tech advance gets you energy security, and performs either neutral or better on two other important axes: financial and environmental.
Efficiency technologies, such as the geared turbofan engines discussed here previously, are clearly a move in the right direction on all three fronts. And here's another new engine tech approach: designing engines that can switch their personalities in flight from drag-racers to econocars and back again. That's the goal of the ADVENT program, which stands for Adaptive, Versatile Engine Technology, run by AFRL at Wright Patterson AFB, with help from Rolls Royce, Lockheed, Northrop Grumman and GE. Note: most of the news on this program is over one year old, so I've got calls into the Wright Pat program office for a refresh. Will post update as soon as I hear back.