That sounds right. I was finally able to find my source related to USN flight training in 1941. As the USN worked to rapidly build up its number of trained pilots, the ratio of instructors ballooned to 1:10 (1 instructor / 10 students). However, they consistently kept the ratio at 1:4 for primary flight training and certain specialized branches where greater individual attention was warranted. I'm currently finishing a manuscript on 12 American flight instructors hired by the Royal Netherlands Navy in 1941 to train pilots on the island of Java. For comparison, the first 2 American instructors to arrive were assigned 7(!) primary flight cadets each a week after their arrival in the Netherlands East Indies.