I bought two Happy Plugs headphones for my kids (ages 4 & 8) to use on a 9 hour flight. Pros - easy to sync, have a capped “high” volume, not too many buttons, comfortable for long wear (if needed), they are noise cancelling but my kids can still hear me when they wear them. Con - sometimes they don’t sync to same device right away. So I have to go into the settings and reconnect.
Overall, I highly recommend these headphones for your kids.