We took our first born on a plane from WI to TX when she was just about 4 Weeks. Surprisingly she didn't get sick but i did! Your immune system is kind of wacky for a little bit too so make sure you are taking care of yourself not just the baby when it comes to things like this.
I don't know if you have thought of this but an airplane is a confined space full of people so lots of germs airborne with nowhere to go. You may want to wait. I would ask your pedi for how long. Most advise waiting until 6 to 8 weeks before getting baby out. Mine is oldschool and that's what he advised. Good luck.
My nephew was three weeks when we took him on a plane from Detroit to Florida. We went to Disney World but my sister stayed in the resort with him she only went to one park which was the Magic Kingdom