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Alternative aircraft and propulsion concepts are urgently required to improve the sus tainability of aviation across all segments. Hydrogen-powered designs eliminate the use of hydrocarbon fuels and offer benefits in terms of emissions. While the mass-specific energy of hydrogen is high, its volume-specific energy is very low; therefore, storage in the liquid phase at cryogenic temperatures is often considered. While several studies substantiated that such aircraft can be feasible, the tank design in general and its gravimetric efficiency specifically are critical aspects that have not been understood in sufficient detail. In particular, the influence of tank capacity on gravimetric efficiency is of interest. The objective of this paper is thus to expose select design trade-offs for hydrogen-electric aircraft with respect to liquid and gaseous tank design and tank dormancy across a wide range of tank sizes. The study is based on a survey of published prototype tank designs, physics-based modeling and simulation, empirical weight regressions, and a recent dormancy estimation method. Here, the explicit consideration of liquid hydrogen storage density on design metrics is a novelty. Three different hydrogen tank concepts of operation are introduced and ranges of tanks are sized accordingly. The best possible gravimetric efficiency is reported in charts as upper bounds of gravimetric efficiency. In the survey of published prototype tank designs, clear evidence for a strong influence of tank capacity on gravimetric efficiency was found for liquid storage. This major trend was exposed via computed design trend lines for the investigated concepts of operation. For gaseous storage, no such trend is found. Correlations of the trend lines are presented. It was also confirmed that additional trade-off of gravimetric efficiency against other, conflicting requirements is possible. Anewsuch parameter beyond pressure was identified for liquid tanks, ullage volume fraction (hydrogen storage density). Accordingly, it can often be beneficial for gravimetric efficiency to store cryogenic hydrogen at reduced density whenever tank dormancy is a design criterion. It was further found that for very large tank capacities this conflict of requirements between gravimetric and volumetric measures can disappear. Finally, the computed trend lines also suggest that, once hydrogen tanks are sufficiently matured on regional aircraft, it is very likely to reach a tipping point beyond which hydrogen-powered aircraft feasibility and benefits improve over kerosene as mission range increases, making hydrogen a superior fuel also for long-range aircraft.