The troopers used to pride themselves on-aircraft recognition. The sun was glaring and the airplane could be seen by none of the soldiers. However, The Professor didn't want even a sight of the plane and announced, "That of course, is a North American Harvard coach. It can be unmistakably identified by the unpleasant engine note, because of the high point speed of the airscrew." The rest felt like louts and felt out of place with Private Quelch.