If you need to fly somewhere with your cat, you can never prepare too soon. Besides getting a cat carrier, you may also want to get training pads (in case the cat goes to the bathroom inside the cat carrier) along with sedatives to keep your cat calm during the flight.
If your cat isn’t used to being around strange places and sounds, try getting your cat used to being in the cat carrier around different areas. The calmer you can keep your cat, the calmer you’ll be trying to fly with your feline.