Rob, you mention the energy inefficiency of splitting water to produce hydrogen. I recently read an article that may change all that. Scientists have discovered that there are numerous formations in the earth where water is chemically broken down into hydrogen and oxygen through a combination of heat, pressure and the presence of iron. The oxygen is consumed by producing iron oxide, and the hydrogen is set free. The reason why these have not been discovered before is that the formations usually contain an anaerobic bacteria that consumes the hydrogen so it never reaches the surface. Some companies are now drilling exploratory wells to see if recovering the hydrogen is practical. If so, it is estimated that the potential is greater than our current reserves of hydrocarbon fuels. And since it is an ongoing process, the potential may be for an unlimited supply of green hydrogen. That could potentially shift electric aircraft to fuel cell technology instead of batteries.