How would you react if you were on a flight where a family was boo'd for being allowed off the plane first to receive their soldier's body?

I would be extremely angry ..

My PTSD would definitely come to the front and I would probably be arrested for trashing the first little booing twerp I could reach.

I would honestly cry because it's sad that a soldier cannot get the proper respect for even giving them the chance to have the freedom they have.

Go Stand directly in front of said passenger and probably do something I might regret later to that said passenger

A simple "WHAT IF WERE YOUR SON OR DAUGHTER; wouldn't you appreciate this gesture of appreciation?" Should suffice.
Even if the rude person didn't "get it", everyone else would and karma has a way of settling the matter in the end.

I throat punch a mother fucker for the disrespect

Treat them look recruits and start yelling at them a boot camp then stop and say then you join the military.

I would let those people that booed know what I thought of them in plain straight forward English.

It'd be an interesting night....and I'd need bail money.

I would move through the line calmly, then grab the jackass by the collar and remind him of what this country costs. Then have him arrested for any trumped up charge I could make stick. Disrespect like that will never shows its ugly face when I’m around.