At the close of WWII, Britain led the world in commercial jet aircraft technology while the U.S. was largely relegated to transport aircraft.
A sad series of tragedies occurred, while British aircraft dropping out of the skies without explanation.
It was unforeseen metal fatigue and it led to U.S. dominance of the commercial aircraft market for decades.
I believe the crashes were caused by metal fatigue which caused the fuselage on the Comet to crack.