flug-review is good
they had the best/most nformative article on scramjets around. the detail they include in their articels is unmatched, I witsh they would buy out space.com and go to work on that.
Their article talks a bit about the worries of outputting h2o in the atmoshere around 11-12 km up, thats right about the line of the upper and lower troposphere, and where the highest clouds extend to 50,000 feet, around the 11 - 12 km range. . . . with all the clouds up there we are afraid the vapor from the engines will somehow make a difference? as if spitting into the ocean is going to cause a flood.
-Justin Kelly