Branched tubular organs are found in most animals. They include tissues like the lung, kidney and the vascular system. Many of the basic principles of tube construction in these organs are conserved among species. We aim to describe the genetic programs leading to the formation of a functional epithelial tubular network. The Drosophila airways, the trachea, form a complex tubular system that delivers air directly to all tissues in the animal. Our work utilizes genetics, bioinformatics and live imaging in Drosophila to characterize the molecular control of tube size and epithelial organ maturation.