It&#x27;s generally accepted that a &quot;hydrogen economy&quot; [1] doesn&#x27;t make sense, and isn&#x27;t going to work.  I think we can say with reasonable certainty that that&#x27;s true for cars where it looks like batteries are going to reign supreme.<p>I&#x27;m not at all sure that that&#x27;s true for large jet aircraft though.  Storing liquid hydrogen is a non-trivial exercise.  On the other hand the larger the tank you&#x27;re storing it in, the easier the problem becomes -- and large passenger jets would by necessity be using very large tanks.  These tanks would be so large that they would impact jet performance in terms of increased drag.  However, even with the larger tanks, liquid hydrogen will still provide a much better energy-to-weight ratio than you can get with jet propellent.  This means you need less lift to fly the airplane and you have lower energy losses to lift-induced drag.  I don&#x27;t know that this would get you to break-even, but it seems likely that a hydrogen powered jet can get comparable performance to a jet using conventional jet fuel.<p>Of course just handling liquid hydrogen is no easy task.  But a large airport should benefit from considerable economies of scale.  It wouldn&#x27;t be like trying to provide liquid hydrogen to cars at your local gas station.<p>There has been at least one experimental liquid hydrogen fueled aircraft, the Tupolev Tu-155 [2].<p>[1] <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Hydrogen_economy" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Hydrogen_economy</a><p>[2] <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Tupolev_Tu-155" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Tupolev_Tu-155</a>