Is that why some drones use motorcycle engines instead of those small rc plane turbines?
Yes. For smaller devices you have efficiency only in range of 5-10% and tiny RC engines still have CR of 8-10, while turbines have it 3-5.
Piston engine CR is about as twice as efficient as turbine one, since it's otto vs rankine cycle - the heat of combustion is contained and pressure increases massively. In turbine you are just heating and expanding air at constant pressure.
Even with that, those turbines only really use 5% of air, the rest is just pumped by as working fluid, so you have immense compression losses - it takes 100MW to drive a 200MW turbine shaft - resulting in only 100MW output.
Where turbines shine is lightness (aircraft) and increase of their total output power with increasing speed (aircraft again), efficiency at high loads (for some reason aircraft again), burning various fuels (military), increase of available power with lower air temperature (aircraft) and low maintenance (aircraft) as well as operation at partial atmospheric pressures (aircraft).
At low loads, they just suck and are just a giant space heaters - In iraq you could see which abrams was turned on, because the entire squad gathered behind it to warm up - so they put an additional power unit to power the internals and keep main engine off.
You may have noticed, that turbines click a lot of stuff for air travel.
The biggest one is - efficiency at high altitudes where air is rarer. Piston engines struggle, since they may loose 50% of their power and require a turbocharger to maintain their output. They did the maths in 1950s and found out, you can get more and more power just by increasing the turbocharger size, until math showed that engine is just a dead weight on a turbo and so MIG3 jets came into flight (engines made by british design)
You can easily imagine standard ground turbine loosing power at high altitudes, so you just slap on additional stage, which is really easy since everything is already moving at proper velocity.
Aircraft maintain their efficiency because they travel at altitudes where air is rarer, so there is less drag.
If you understand that modern cars top out at around 200kmph where the air resistance matches engine power you can understand you either need a more powerful engine to go faster or reduction of drag.
Planes do both and as a reward, they can go much faster so the inefficiency of propulsion system is outweighed by efficiency of very very fast travel.
Satellites travel at 12.000km/h and they use 0 fuel because there is no drag.
