Blimps can show up on radar, but their visibility depends on their construction materials and size. Unlike airplanes, blimps can be made from non-reflective materials, allowing them to potentially avoid radar detection more effectively. The presence of metal components, such as the cockpit or engines, can create reflections, but these may not accurately represent the blimp's full size. Additionally, environmental factors like rain can influence radar reflections, raising questions about whether a wet blimp would be more detectable. Overall, the design and material choices of blimps play a crucial role in their radar visibility.