Personally, this isn't for our family. We flew with LO for 4 hours for the first time a month ago, and I was extremely anxious about the whole thing, but LO handled it like a champ thankfully. There were a lot of people on the flight (200+ I believe), but the flight attendants were amazing with him and we even found another family with a toddler that we talked with and our LOs played together.
We were also considering flying to China to visit my father, but decided to wait until LO was older since that is quite a bit longer of a flight. I don't think he would have been "traumatized" or anxious because of the flight, but I do think that I would have been asking for trouble by making him sit for that long
I personally feel like if you know your child well enough to know that they will get extremely anxious on a plane and you don't absolutely need to go on a plane, then why not just avoid it all together? We don't give our LO medicine at all so we never considered giving him something to put him to sleep for a flight, but I think depending on the plane company you go with, the flight attendants are great with the kids and actually pretty helpful.