The academy, though it could be considered a single school made for young dragon warriors, was actually made up of different schools within it, these schools were designed to teach and train specific dragon warriors.
The school of water trained water dragon warriors like Susan, the school of fire trained fire dragon warriors like Steven, the angry boy that almost fought David, the school of earth trained earth dragon warriors like the boy with black spectacle and finally the air school thought air dragon warriors like David and Flora.
Flora had shown David the other schools of the Dragon Academy, explaining what they were and warning him to never go to any other school apart from the school for air dragon warriors as students were not allowed to interfere in the affairs of any other school apart from theirs.