Six week old infant rescued from plane crash in 1957.
https://www.atlasobscura.com/articles/rikers-island-plane-crash
This ends that debate:
The Patient in Commercial Jet Aircraft
Robert B. Stonehill, MC U. S. A. F.
From the Department of Medicine, U.S.A.F. Hospital, Lackland Air Force Base, Texas
July 9, 1960
JAMA. 1960;173(10):1121-1123.doi:10.1001/jama.1960.03020280061013
“Infants. — It is usually advisable for infants delivered at term not to fly at less than 7 days of age, because of the immaturity of their respiratory apparatus. After this, the airlines have had no difficulty carrying these babies. Nursing of infants during the descent in flight helps maintain the patency of the eustachian tubes and prevents aero-titis media.”