Case interview skills are actually very portable, so once you really understand how to crack one type of case, it will be much easier (reasonably easy) to crack another case. From that perspective, yet it would be worth your while doing other cases as well. Ok to do cases specific to transportation obviously, but don't constrain yourself needlessly if you run out of case scenarios
My main recommendation to you is one of caution: often when the candidate is familiar with a topic, he/she doesn't listen to the actual question very well. Feel free to bring in a little bit of your industry knowledge, but make sure you don't assume a specific question or answer just because you saw something similar in real life. When I was in your shoes, this is why I actually relished cases from industries I knew nothing about.