The linked article basically answers the question. The physical shape of the trachea, carina, and right and left mainstem bronchi was created from glass. Over the course of two days, that glass became lined with the patient's cells.
To be clear, the claim is not that the glass was replaced by human cells over the course of two days.
Those are two totally different questions. To grow a complete trachea in two days would strain credulity. To get a glass template lined with cells in two days seems quite reasonable. Not sure about the specific cells that they used, but other cell types that I have had experience with will become confluent after starting off at a modest concentration within 24-48 hours.
To be clear, the claim is not that the glass was replaced by human cells over the course of two days.