Actually child benadryl is not uncalled for during a flight, especially if they have a head cold or sinus infection.
I used Benadryl on my son when he was fussy on flights. Fast forward....my husband, 16year-old son and I took a cross country flight from Boston. There were several bratty kids and an infant who had been crying non-stop for 2 hours. With a few hours left I saw the mom by the lav and suggested she try some Benadryl. She was pretty horrified by the thought. I told her that the child was in misery and that it would benefit all if she tried it. She glared at me the rest of the flight. A little Benadryl wouldn’t have hurt the fussy child and a couple of hundred people would have been grateful. Now........how to deal with kids who play their portable DVD players loudly and without headphones???
I was told by my pediatrician not to use benadryl on my child when flying many years ago.