And since you also asked about aeroplanes:
The most common situation in light aeroplanes is to have two levers, one for the throttle, and one for the propellor.
The throttle lever directly controls a throttle butterfly just as it does in a car engine, or in almost any other piston engine.
The prop lever controls the RPM. a Constant Speed Unit (CSU) is used to automatically adjust the blades to an angle which gives the appropriate RPM. A change in either power or airspeed, both of which would change the RPM if the pitch of the prop blades was fixed, instead causes the CSU to adjust the angle of the blades to maintain constant RPM.
In general, an increase in power is accompanied by an increase in RPM and vice versa. In this case, when increasing power, the prop RPM is increased first, then the power. For a decrease, the power is decreased first, then the RPM. This sequence ensures that the engine is not damaged by applying high power at low RPM. (Imagine flooring the accelerator in your car, in top gear, at 10mph.)
There are other setups, though. In the aircraft I fly, the pilot directly controls the pitch of the prop blades, there is no CSU to do this for you. Although there is no problem with applying too much power at low RPMs with this setup (the engine/prop combination has been designed to not break even at full power and full coarse), there is a danger of overspeeding the prop at high power, moderate-to-high airspeed, and with the prop blades set to fine, so this is the main area you need to think about, especially at the top of the climb.
Many turboprops use just one lever, which sets the engine power directly. I believe that these aircraft will use a CSU to maintain a sensible RPM based on the position of this lever.
Hope that's some help.
FFF
---------------