Is it normal to think that kids under 10 should not be allowed on planes?
You know all those stories of kids crying/horribly misbehaving on planes? Well, I believe that any kid under the age of 10 (as well as poorly disciplined) should not be allowed anymore. It's inconsiderate to the other fliers and if they wouldn't ruin your flight with a screeching, misbehaving child, I think you owe them the same courteousy.
They do not belong on planes. If bringing babies, toddlers, and young children is absolutely neccessary (like, emergency neccessary, not just the parents being rude), is to make Adult-Only Flights and Parent & Child Flights.
I feel the same for buses, trains, theaters, etc.