When is it really safe to fly after mastectomy/reconstruction?

while I realize this likely depends on the type of mastectomy and reconstruction you have done (expanders vs direct to implant vs  flaps like DIEP) I've heard different things from different doctors in regards to how soon you can fly home after surgery.  some have said 10 days later while others say you must stay a full month. Very confusing  and hard to know which is correct or truly necessary. What is really the safest time frame? When is too soon?  Is there really a difference between waiting two weeks versus waiting a month to fly home on a 4.5 hour or less flight?Thanks-