The fastest "real aircraft" was the SR-71, and it was already ridiculously expensive to keep it running at just above Mach 3. The program was cancelled due to costs, too expensive for what it was providing in the age of cheaper and better satellites. We (as in humans) couldn't even keep the expensive Concorde going, and the Concorde was delivered free of charge to British Airways and Air France. This project is just a wild dream.