LiveScience reviews recent concerns that large numbers of space planes, which are in planning stages, could be really bad news for the atmosphere because of soot and carbon dioxide.
Some years ago similar concerns led to quashing plans for fleets of supersonic aircraft. The Concorde was something of an anomaly in that it was permitted because there were a limited number of them, and hence minor damage would result.
As the wikipedia article relates:
In the 1960s environmental concerns came to the fore for the first time. The SST was seen as particularly offensive due to its sonic boom and the potential for its engine exhaust to damage the ozone layer. Both problems impacted the thinking of lawmakers, and eventually Congress dropped funding for the US SST program in 1971, and all overland commercial supersonic flight was banned.
Will it be so easy to ban or similarly limit the space plane industry? Times are different now. I wonder what Richard Branson will say.