Your parents' views are, by current standards, out there. Getting in their faces about it would be needlessly disrespectful, but there's no reason for you to tiptoe through their delusional little terrarium as if you can't bend even one blade of grass.

I realize that people fly with small children all the time, and that babies are easier in some ways because all they do is sit/lie around anyway, but damn it's hard to keep a baby comfortable on any flight, much less a long one, particularly amid the looks of horror they will get from fellow passengers as it dawns on them that their 10- to 13-hour flight might come with a soundtrack of screaming baby.

A lot of support gets withheld out of fear of awkwardness and misspeaking.

It's hard to send your baby off on a plane without you, though that's less reasonable, because sending him off in a car is statistically a bigger risk.

One helpful thing to keep in mind as a retort-stopper is that you won't "win," you won't change anyone's mind, you won't change any votes, you won't make the atmosphere in the room any better, YOU won't feel any better.

You need to make plans for your future, so plan your own future.

Apparently you have ample proof from experience that you're not going to stop world evil by debating your in-laws into submission, so it's okay to choose not to try.