You should use the newest patcher, v1.0.46.0. The crew will detect radar signals from ships AND airplanes
I'm kind of half amazed it's all working correctly
@ Trevally - I had to edit your aiplane test mission to remove the ships so there were only airplanes in it. Radar operator nailed the airplane from a good distance out. He was all over him once he detected him. Never lost that green line!