Pretty soon he is hitching a ride on the rear bumper of a jeep full of brass. The airfield is still ringed with ack-ack guns, and shows signs of having been bombed and strafed not too long ago. Some of these signs are obvious physical evidence like shell holes, but Shaftoe gets most of his information from watching the men: their posture, their facial expressions as they stare into the sky, tell him exactly what the threat level is.