Think of that big wheel on The Price is Right. It takes quite a bit of force to get that thing moving. Once it’s moving it spins freely, but that’s not what we’re concerned with. We’re talking about rotational acceleration. Now imagine the wheel instead of being mounted in a fixed position, mounted on the end of a pendulum. Now spin the wheel, but instead of pushing down on the wheel to turn it, push it along the arc of the pendulum. What happens? The wheel begins to turn but is also pushed along the arc of the pendulum. The amount of the spin (speed and time) is directly proportionate to the amount of thrust (your push) that was used to overcome the rotational resistance (inertia) of the wheel and not used to propel the wheel forward (hence wasted). Looking at it from this point, if enough rotational inertia (the conveyor belt going faster and faster, continuously exerting more and more rotational resistance) is exerted, all of the planes thrust will be used just to overcome it and the plane will not fly. This theory requires a super god-like conveyor belt which completely ignores the very rules it is using to keep the plane in place, but under these circumstances the plane will not fly. However, if the plane’s wheels have zero mass (thereby bringing the wheels into the same la-la land as the conveyor belt), and therefore zero rotational resistance (inertia), the plane will fly.
As far as automobiles go, rotational inertia is very important. Lighter flywheels, drive shafts and wheels are all used to make engines rev faster (as in getting from one rpm to another more quickly) and to make cars accelerate faster.
Another example of rotational inertia is a car engines torque. Back in the old days when you put a car in neutral and revved the engine up it would rock from side to side. Today when you do that the car rocks back and forth (most front-wheel-drive cars have the engine in sideways…). This is a direct result of the engine reacting to the rotational inertia of the crank shaft and the fly wheel and is also an example of energy loss due to the nasty laws of physics.