There were several, both on the planes and in the WTC, although I can't find any source that lists them all. There appears to be a person holding a baby in the center of this gut-wrenching photo:
Upon further, closer inspection, the baby in the picture isn't a baby, but a person in a white long sleeved shirt leaning out the window.
I thought so first, but when I went to check it closer, it became more clear.