Flying after surgery may be limited by decreased mobility and crutches as well as with long-haul flight be associated with increased risk of blood clots. I will be happy to provide individual advice regarding this at your request.
In general it is advisable to avoid long-haul flights for 42 days after knee or hip joint replacement surgery and 21 days after arthroscopic knee surgery. Short-haul flights may be undertaken in some circumstances. If you must fly you must take extra precautions to prevent blood clot formation.