The amnesiac flight attendant storyline was not bronze age
It was golden age.
Golden Age of Comic Books (1938 – 1956)
Silver Age of Comic Books (1956 – 1970)
Bronze Age of Comic Books (1970 – 1986)
The Amnesiac Flight Attendant story was Batman #62 which was published in 1950 and 6 years before Silver Age story.
Therefore, it was in the Golden Age.
It definitely wasn't in the Bronze Age which started in 1970.