Looking for a novel in which newborn babies are taken up clinging to the wings of their father's aeroplane, so weak, sickly babies die [duplicate]

Question

I think I this was a novel, but it is possible it was a short story. I read it in the 80s.

There is a future, technological society. Almost every family has their own private aeroplane, they are analogous to cars in our society.

When a baby is born, the child's father takes them for a test. They must cling to the wings outside his aeroplane as he flies. If they lose their grip, they fall to their death. The idea is that only strong healthy babies are desirable.

An educated man is explaining why he does not like this custom of testing newborns thus. He says that while the practice does get rid of weak or sickly infants, of the healthy ones, those with the more primitive hand grasping genes are more likely to survive. He says these babies are likely to be of below average intelligence.

Answer 1

This is a small incident in Olaf Stapledon's Last and First Man, taking place in the relatively near future of a few centuries hence (the book covers two billion years), in an aeroplane-dominated society:

In the life of every individual, flying played a great part. Immediately after birth he was taken up by a priestess of flight and dropped, clinging to a parachute, to be deftly caught upon the wings of his father's plane. This ritual served as a substitute for contraception (forbidden as an interference with the divine energy); for since in many infants the old simian grasping-instinct was atrophied, a large proportion of the new-born let go and were smashed upon the paternal wings. At adolescence the individual (male or female) took charge of a plane for the first time, and his life was subsequently punctuated by severe aeronautical tests. From middle age onwards, namely as a centenarian, when he could no longer hope to rise in the hierarchy of active flight, he continued to fly daily for practical purposes.

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Consequently the only restriction on population was the suspension of the new-born from aeroplanes, a process which, though it eliminated weaklings, favoured among healthy infants rather the primitive than the highly developed. Thus the intelligence of the race steadily declined. And no one regretted it.