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 s

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.