Wear Layers
It is possible to feel warmer or colder in the air when flying, depending on where you are in the plane, the flight altitude, and the number of people who have turned their air conditioning on or off. As a result, it’s advisable to wear layers of clothing to deal with unpredictable temperatures.
If the temperature rises while you’re in the air, you can always remove clothing until you’re comfortable, and the same is true if the temperature falls while you’re in the air. This will allow you to, at the very least, feel slightly less uncomfortable, which is especially important on extended journeys.