I need to limit the development of the internal combustion engine so that it is only available in small numbers to few individuals and does not progress technically, or at least only progresses slowly. I want something that can power a large airship, but perhaps only just.
The background is a world that supports human life but is not the Earth. There is roughly 1g gravity and plenty of water but little land. The atmosphere is very thick and the only populated areas are large plateau islands raised high up where the atmosphere is more bearable. The story will revolve around the development of airships in this world but I want them to be developed in small numbers by some eccentric rather than as a state based or wide spread option. The level of technology is roughly 1800’s but does not have to follow our time line (some things may be invented early other things being late if it can be justified).
Other details can be manipulated to suit. I thought that the internal combustion engine would be one of the key constraints for a working airship but bonus if anyone can suggest a better choke point to limit airships instead of the internal combustion engine.