I can only respond to a woman, since my husband is warm in a fleece jackets no matter the weather.
If you wear a sheitel, snood, you will be fine, if not bring a hat. Always bring a scarf & gloves. In skirts, you will need warm boots.
The weather right now, during the day is coldish – needed a warm coat for shul today. I, and most of the women in Shul wore knee-high boots.
Is is easier to open the coat, leave the scarf & gloves where you are staying, then trying to stay warm without them.
Just wear the boots, coat & scarf on the plane, so it takes up no room in your luggage.
To me, there is nothing worse than being cold.