Flighty often does come from the chicken cuddly sorts. To some, if it flaps it's wings it is flighty. The reputations can become over extended. If I had read the books, I would have known that my Catalanas were flighty. I did not, so I do not. What I have are birds that are sharp, assertive, and active. They are confident, not nervous.
Some strains of some breeds are down right nutty. They are no pleasure to own. So, some could be called flighty while being fair. It is a subjective term, so each will have a different view.
But let us be honest. Many do not want real chickens, LOL. They want them soft and cuddly. And there are trade offs. Calm can be synonymous with lethargic. I prefer active and with personality. I like to see something going on upstairs.
Then, much of it is management. Some birds are not meant for close confinement.