You should definitely take warm clothes with you on a plane, along with your carry-on luggage. And not just to warm up if the cabin gets cool: this is an important safety measure. For example, due to oxygen deprivation that occurs at high altitude, a passenger can lose consciousness; with the help of warm items, it is easier to provide them with a comfortable position.
During shaking that occurs in turbulence zones, they prevent injuries, and in the event of a fire, they will protect against hot air and flames. Of course, this is true if the clothing is made from natural fabrics—synthetic materials, on the contrary, ignite instantly. During an emergency landing in inclement weather, warm clothing will also come in handy. In case of rain, it’s worth putting a raincoat in your carry-on luggage as well.
Well, and for their direct purpose, warm things will also be useful—the cabin usually maintains a temperature a little below average, since at high altitude the metabolic rate increases, which often leads to overheating. It’s impossible to calculate what temperature will be comfortable for everyone, so you, in particular, might very well be cold.
