I had to look that up. A 747's max fuel capacity was 63,705 US gal according to [https://en.wikipedia.org/wiki/Boeing_747 https://en.wikipedia.org/wiki/Boeing_7

I had to look that up. A 747's max fuel capacity was 63,705 US gal according to [https://en.wikipedia.org/wiki/Boeing_747 https://en.wikipedia.org/wiki/Boeing_747] and jet fuel is around 3.25kg per gallon, so ballpark of 207,000 kg or 207 metric tons could go into the biggest 747s. 7 metric tonnes is about 2,150 gallons. Interesting stat. Isn't a lot, but it sorta is, too.