It's actually much more complicated and much simpler at the the same time, than all of the above.
The reason that aircraft fly is a result of the sound that is produced in the pursuit of entropy. Early aircraft were very loud for not much load or speed, the DoX for example had sixteen sound engines for about 100kts flat out with a dozen pax, but fortunately aerodynamic engineers have worked out how to get a much more efficient use of sound over the years. The new wide chord fans are a great example of this efficiency gain.
The bigger the aircraft the greater level, as distinct from volume of sound is required to "shake" itself between the air molecules and the ground thus producing what we quaintly call 'lift'.
It also explains why the higher the altitude the less actual noise is required, there are less air molecules to pry apart.
See.
Ever noticed how it's actually quite hard to "hear" an aircraft flying overhead at FL350 from the ground.
It is also why you don't see your average space shuttle running its engine as it orbits, no, or very few air molecules, to pry apart, so no sound required.
Just think of the proportion of time taken up in our training for dealing with the eventuality that it becomes quieter than normal or even
totally silent.
Ergo it's all to do with the amount of sound.
Less or no sound is a pilots worst nightmare.
Turbofan, there 'tis, simple really, I hope this makes you sleep a little easier.
