Significance of Aeroplane engine sounds in The Wind Rises

In the movie The Wind Rises the Aeroplane engine sounds are voiced by humans.

Is this meant to signify the soul in the plane? The human in the 'beautiful dreams' that are Aeroplane to Hiro?

What is the significance of this human voicing of the planes?

Best Answer

Because Hayao Miyazaki wanted it like this:

The most striking thing about “The Wind Rises,” though, are the images rather than the politics. It’s easy to fall under the spell of the sheer beauty of the film, with its soaring vistas and an array of sound effects — trains, airplane engines and the like — done by mouths, not machines. “Originally Miyazaki wanted to have all the sound effects voiced, and he wanted to do them himself,” said Wexler. “They said ‘No, we need you to draw the film.’ - THEWRAP

This doesn't serve any real value to the film's deep analysis and was even criticized by some.