I saw a hydrogen one the other day. One problem is both methane and hydrogen are low density gasses and require pressure vessels = linits load. You could fuel w

I saw a hydrogen one the other day. One problem is both methane and hydrogen are low density gasses and require pressure vessels = linits load. You could fuel with liquid methane or Hydrogen, as a small dewar flask of superinsulated pod would be light in weight, but would have limited shelf life. Catalytic break down of alcohol to Hydrogen might work?