air passage
air duct
airway *

And then some air ducts, that stuff was falling down.

Then she got into the air ducts, big fat ones in a building that age.

Maybe the whole lower level was only air ducts or for flood control.

And then she moved inside, feeling the walls of the air duct against her scales.

They know more of the air ducts than we have asked them to learn.

"Then you better just block off the air ducts, too!"

One way or another, it was time to get out of the air ducts.

It is said that you and he were together in an air duct for two days.

The marble came to an air duct and rolled into it.

There may be times when you will want to add or modify an air duct.