The problem with hydrogen, in addition to the difficulty of storing it in an airplane, is that the most practical way of getting it is by electrolyzing water. With electricity. From what is usually a fossil-fuel power source.
There's lots of work being done on bio-fuels in the past few years. The US Air Force is very interested. Unfortunately, considering how incompetent the USAF seems to be on its major development programs, that may not be a good thing.
Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.