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.