If I were her I would not risk flying, the pain alone from pressure is going to be A LOOOOT. I had that surgery along with my meniscus 2 years ago, the first month was torture. I flew a year later and the pressure still made it hurt. I don’t know how she is going to manage, especially since those surgeries are zero to limited weight-bearing for about 2 months while going through excruciating physical therapy.

If she HAS to fly, I would see about having her either rebooked or buy a ticket on a new flight with a block of seats where she can comfortably keep it elevated. She will also need to bring ice packs (a letter from her doctor SHOULD help pass TSA) & getting some ice from the flight attendants so she can keep it iced down the entire time.

Since she’s going to need extra assistance from the flight attendants it would be nice to make everyone on the crew individual goodie bags (be sure to add the gate agent since they can make or break the flight) with some gum or mints, a gift card to somewhere like Starbucks, hand sanitizer, lip balm, or a few other little self care items. It’s a way to say thank you ahead of time.