Why does the Zapata Flyboard Air UL consume so much more fuel/hr than the Mosquito Air? They are both ultralight and abide by FAA ultralight reg 14 CFR part 103.  The Mosquito Air is an ultralight 1 person helicopter whereas the Zapata Air UL is a micro jet turbine powered 1 person ultralight hoverboard. They weigh the same and both only carry 5 gallons of fuel as this is dictated by part 103.

The 5 gallons will last 1 hour of cruise flight time on the Mosquito while only 8 minutes on the Zapata.  Granted we are dealing with different technologies here and different fuels (Zapata uses kerosene, Mosquito uses avgas) I was surprised by the fuel burn difference.

The bare physics tells us that equal masses should require the same amount of thrust, thus energy, to hover in place where lift equals weight.  Kerosene has similar energy density to avgas.  And, a jet turbine is supposed to be much more efficient than a 2-stroke, 2 cylinder gasoline engine.

The Mosquito boasts of a 64hp engine "with the highest power to weight ratio on the market today".  The Zapata company seems not so much concerned with the gas guzzling fuel consumption.  The 2 companies seem to have different priorities here, so I'm guessing the fuel efficiency of the Zapata could be improved.  Still, this is a huge difference that is difficult to understand.
It's the difference between jet engines and propellers. It is a lot more efficient to accelerate more air to a low velocity, than it is to accelerate less air to a higher velocity. For fixed wings, the only reason to use jets is if propellers hit their speed limit, when the tips break the speed of sound.

Hovering flight is particularly demanding on fuel consumption. The Mosquito Air burns through its fuel a lot faster than 1 hour when it stays in hover all the time. Cruising in a helicopter makes the fuel consumption  a bit more similar to fixed wing: the rotor blades start to act more like wings and can use airspeed to reduce induced drag. Still less efficient than fixed wing cruise, but more efficient than helicopter hover.

The Zapata Air UL is always in a hover, and has no wings, and is a jet. It never gets the increased efficiency effect of forward flight that a rotor gets. And jets are really very inefficient at low speeds!