In the version I was told (by a French ex-military airline pilot) Ziegler's father was present for a ceremony in the valley at the time of the cable-severing, and that, in fact, was why sonny was there, showing off. The cable apparently passed between the wing and a drop tank. Daddy was head of Air France too, at one point. French aviation is very incestuous. One wonders what the little Zieglers are in charge of.
This, from Time in 1961:
"The small, shiny aluminum cable cars swayed in an endless, airy line high above the Alpine stillness of the Vallee Blanche. On either side the passengers could see the granite buttresses and whitened peaks of the Mt. Blanc massif. Far below gleamed broad glaciers and snowy crags.
Then out of the sky hurtled a French air force F-84F jet fighter. It sliced in two the cableway's traction line, losing a wing tank in the glancing blow, then soared out of the valley. The severed cable cracked like a whip. Three of the cars tumbled 500 ft. to earth, killing all six of their passengers. "They fell like ornaments from a Christmas tree," said one shaken observer. In the remaining cars, 81 other passengers dangled helpless in space. Mountain guides worked their way close enough to rope some of the passengers to safety. It took cableway technicians using hand cranks 20 hours to rescue the last car and its passengers.
As French police opened an official inquiry, Jet Pilot Captain Bernard Ziegler could only recall his plane striking "something." "Airplanes don't belong up there. Maybe people don't either," said one survivor, "but planes are as out of place as pagans in a cathedral."