I’ve seen cherubs (flying or floating, usually naked, babies / toddlers) in a variety of religious paintings. Even in paintings where only the head is represented, they tend to be playful sprites or sleepy / cuddly companions. A lot of these paintings were commissioned to be displayed in churches, especially to an illiterate populace. But child mortality used to be quite high, especially for children under 5yo, and Catholicism is pretty specific about what happens to unbaptized babies. So how would an average illiterate person (who had likely buried one or more young children) understand these symbols?
So... you're asking for what illiterate people who therefore wouldn't leave us firsthand records would have thought in an unspecified time period?
As regards the Catholic Church's teaching, it's perhaps not as specific as you might think:
It teaches: (1) Unbaptized babies do not automatically go to Hell; (2) Knowing that God is a merciful God, the Church entrusts these children to His mercy; theologians speculate, though it has fallen out of favor (3) that God provides for these children a place of natural pleasure, that, while not heaven, is not hell - "limbo"
( Vatican Link )
Moreover, as far back as John Chrysostom (AD 400), the Church has held that for miscarried children of believing parents, God honors the intent of the parents to have had that child baptized if they could.
Finally, although many folks often delay it, it is customary for a child to be baptized within a month of their birth - and at the hospital if there are any signs of medical difficulties.