I have had a Revell Goodyear Blimp on my layout (hanging from a piece of coat hanger and electrical wire) from the top of my background) since at least 1985. It is a snap together kit and has a two D cell operated Lighted Moving Message Board. I have not used the Lighted Moving Message Board as it eats D cells (has three 3v flash light bulbs in parallel and small dc motor) and it is a pain to disassemble it, to change the D cells. The model Blimp is 13 inches long and 3 inches in diameter and scale size here is not that important as a blimp is in the air and seen at various distances. The kit was sold new in the 1970s and 80s and is available on eBay in various conditions. I painted mine silver and the stabilizers red and blue.
Recently I found a 9vdc, 1000mA wall-wart transformer and used a Buck converter (learned about them on OGR forum) to make its output 3vdc. I bypassed the ON/OFF switch, which was on one stabilizer, as it was of poor quality. So now I have a train board Operating Accessory, a Revell Goodyear Blimp, with operating Lighted Moving Message board, . It came with several pre-made message sheets and spare paper sheets to make your own messages with colored pens (that came with the original kit). It even has a noisy geared rotating mechanism, like a real blimps noisy twin airplane motors and propellers.
Charlie