Interesting documentary about Skylon:
However, I think it underestimates the fundamental problem with Skylon. It’s very clever, but suffers from what you might call ‘Apollo Syndrome’; it’s very much an all or nothing design which needs huge up-front investment with no guarantee of success. Without that multi-billion dollar investment you have nothing of use, which effectively limits it to a government program as few companies can afford to take that kind of risk.
SpaceX, for example, expects to reduce launch costs to Skylon levels when they have a fully-reusable Falcon, but they don’t need to invest vast amounts of money to do because they can make money from the expendable Falcon first and work toward the low-cost reusable design. The best suggestion I’ve seen for Skylon is to use it as a hypersonic airliner, but that still requires doing most of the work and there’s no proven market.
So will it ever fly? I’d like to think so, but I honestly can’t see how they’ll convince the people who have enough money to give it to them.