NYTA

The more I fly Middle Eastern/European carriers that keep the temperature warmer, the more I see the need to dress in layers. I typically wear a T-shirt or dri-fit shirt, Jacket or sweater and a stuffable down jacket in my carry on. Despite this I'm still often hot in just the T-shirt. I find the middle of the A321 to be quite hot all the time so try to sit way in the back or front if possible.

Bagels

The OP reminds me of the guy who shows up to the office in a t-shirt and jeans on casual Friday, then hauls out the space heater -- despite the fact that it's hot & sticky outside, and the office is conditioned to 75 degrees -- just because he's cold.

In my lifetime, I've been fortunate enough to have traveled on a couple thousand flights or so; unless there's a maintenance issue, they just don't get "bitterly" cold for prolonged periods of time - that's absolute nonsense. If you're somebody who has the tendency to feel like you're cold, then dress for the occasion and bring a blanket.

For years, I flew on early morning FNT-DTW DC-9 departure, and during the winter, that thing was insanely cold, despite the fact that NW had an employee whose sole job was to ensure the aircraft reached a comfortable temperature before passengers boarded. But once the engines started, the cold dissipated. Moral: board last, not first.

Tizzette

The thermostats are set for the comfort of the workers. FAs feel warm enough because they are moving around wearing fairly warm uniforms. Same as the wait staff at restaurants. Same as offices where men wear suits. Same as any event with an energetic speaker in a suit moving around while the audience freezes. I board wearing a sweater or fleece and in my carryon on, I have another sweater and whatever jacket or coat for the weather where I am going. Part of the answer is for FAs' uniforms to be lighter weight and cooler.