You'd use LH2 or ammonia rather than compressed H2. All else being equal, cruise power for an aircraft is linear with mass, and LH2 has 1/10th the mass for the

You'd use LH2 or ammonia rather than compressed H2. All else being equal, cruise power for an aircraft is linear with mass, and LH2 has 1/10th the mass for the same volume. For a 40% fuel fraction, an aircraft with liquid hydrogen comes in at 65% of the weight and 25% of the energy content for the same volume of fuel. This will get you a bit under 40% of the range of the kerosene jet, if both jets are equally efficient. Ammonia is fairly similar, maybe a few percentage points higher. You could probably get more than 50% of the range of existing designs using fuel cells that are more efficient than jet engines. More likely we're looking at a rethink of how we design aircraft to accommodate larger volumes of fuel. If we did this, we could approach currently used fuel mass fractions with LH2, and potentially go further than we do with current aircraft. Keep in mind the effective energy density of ammonia after taking efficiency into account is still ten times the energy density of today's state-of-the-art lithium ion batteries (by mass). LH2 is of course much higher than that. I find it hard to see batteries replacing anything other than short hop flights for the foreseeable future, if that. Fuel reserve requirements alone make it a tough proposition.