I too first believed it was a small aircraft that struck the tower. Then wondering how on earth a jetliner could have made such an error. Of course, the real truth was horrifying.
My oldest daughter had just started her first year at Dayton and worrying about her. I knew that while all commercial traffic was grounded, that planes would be flying in and out of Wright Patterson.
My wife had gone to an employment seminar that morning and she didn't know until around lunch time when one of the other participants came in late and told them. She didn't fully understand the gravity of the situation until she got home.
My son was still in grade school and the school chose not to inform the kids, so they didn't know until they got home.