BMW recently released a hydrogen car
http://www.greencarcongress.com/2006/09/bmw_announces_m.html

The car has 8 kg liquid hydrogen in the tank. How much does the tank itself weigh?

How much would a tank weigh that has to hold 80 kg or 800 kg or 8 tons or 80 tons of liquid hydrogen? Is the answer different if the tank has to fit the shape of, e. g. wing interior?

BMW says the heat leak in a parked car tank causes a half-full tank to empty in 9 days. The released hydrogen is catalytically burned - where does the heat go?

I presume that in a parked, non-defueled plane you should leave some engine or APU running in hotel mode on the boil-off hydrogen?