IT ALL began with a tennis dinner. The year was 1981, and 47-year-old Captain Brian Walpole was flying high. As one of the ...

However, the jet was criticized for its inefficiency. Compared to a Boeing 747, the delta-wing Concorde guzzled four times as much fuel and carried only one-fifth as many passengers — around 100.

The XB-1 is a pint-sized testbed for the Overture: a next-generation supersonic airliner developed by ambitious US startup ...