As a parent who has had the dubious pleasure of flying with children of my own and experiencing the children of others, here's a far more important takeaway:
As shitty as it is for you to experience a miniature crying human, it is ten times shittier for the parents. The emotion you should be reaching for is pity—for the child that can't communicate its desires, and the parents who are desperately trying to divine what baby wants before dying under the weight of every. single. person. staring. at. them.
As for the parents who apparently "ignore" their misbehaving kids—there are no lack of poor parents out there, but more often than not, ignoring is the fastest path to ending a tantrum ("don't feed the trolls"). It's doubly difficult to do when a plane full of people are giving you the evil eye.