[TylerE]

A lot. Perhaps 75 gallons/hr. Jet fuel is currently a about $1/gallon.

Even a much smaller plane like a 172 can easily burn $50/hr just in fuel. Much lower flow rate, but it’s leaded a gas at about $4.50/gal

[PunksATawnyFill]

Way more than that these days. There’s only one supplier of 100LL, and even they don’t want to be in the business anymore.