Our kids (as young as two 2 year olds and a 5 year old) used to get compliments in the restaurants for being so well-behaved. Of course it took a couple of times walking out of a McDonald’s or ice cream store without getting anything for them to get it.
“Nope - sorry. I told you earlier, if you can’t behave we would leave. No playing in the play area, and you can have peanut butter sandwiches when we get home.”
The twins were so excited to go on their first plane trip, I suppose they were six. Once we got up to cruising altitude they both said “This is it!?” Of course we had all sorts of drawing stuff and books and stuff for them as we flew coast to coast.
Having something to do is critical.
Heck, I get bored out of my mind on long flights with nothing to do. I just have learned enough self control to not act out.