Hypersonic possibilities

When it comes to reviving high-speed air travel, it all comes down to propulsion, propulsion, propulsion.

Over the decades, much research in the U.S., Europe, Russia, and Japan has been undertaken on aspects of ultra-high-speed flight, including radical airframe shapes, the use of unconventional materials, and ramjet and hybrid engines. Although Russia developed, and for a brief period in the late 1970s operated, its own Tu-144 supersonic air transport (and used it mostly as a high-speed freight carrier), only the Anglo-French Concorde resulted in scheduled-service supersonic passenger air traval.

Work on follow-on supersonic air transports continued in the 1980s but none of it came to anything, as rising fuel prices and environmental concerns killed off enthusiasm for speed. The industry concentrated instead on making conventional aircraft that were quieter and less fuel-thirsty.