I am traveling to get my BBL will a happy booty pillow fit in an airplane seat? I will be waiting a couple weeks post op.

There are no hard and fast rules on when to fly or how to sit when flying after a BBL.  Most would recommend a week or two before flying.  This question is best answered by the PS who performs your BBL as he/she will have his/her own post-op guidelines and will be aware of any complications you experienced during surgery and post-op.
The main risk that would be the most serious in sitting on the plane:  development of a blood clot in the legs that can then migrate to the lungs. Sitting for long periods of time puts you at higher risk due to being stationary.  You can obtain a letter from your PS requesting that the flight attendant allow you to stand when the seat belt sign is off, and walk the aisle every 30 minutes. Use your pillow to take pressure off the buttocks and place it under the thighs.  Pressure on the fat, etc. are also possibilities. but it should not impact fat survivability provided that frequent breaks from sitting are taken.My LVN helps all my patients matriculate from the recovery room to their mode of transportation to ensure that they are comfortable and safe.  He reclines the seat at a 45 degree angle and places a folded pillow under their thighs.Kenneth Hughes, MD, Board Certified Plastic SurgeonLos Angeles, CA

You should wait at least 2 weeks before sitting without a support cushion and sleeping on your back. Sitting with no support too soon can harm the newly moved fat cells.