We're talking about fiction. If you can't recognize it as technology or civilization, how do you plan to write about it?
As for combustion, indeed, other planets may not have it. So how do you propose that they would start to develop a technology which would lead to building spaceships?
As for combustion, indeed, other planets may not have it. So how do you propose that they would start to develop a technology which would lead to building spaceships?