Space question: Looks like several countries are still working on spaceplanes. Is there a reason to do this now that SpaceX (and presumably soon Blue Origin) are doing reuseable rockets?
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Could there be some savings by using air-breathing engines to get into upper atmosphere then change over to rocketry for the final push to space? I know that was the original use case, or one of them.
Not unless you're going very very big, like the Skylon is trying to do. In this case you're forcing an SSTO, which means you're carrying useless mass into space, while a reusable rocket gets much of the same advantages with a much higher payload.