Technically it would be reasonably safe to fly for less than an hour 4 days after a lower facelift, but it would not be recommended. Although a lower facelift is cosmetic surgery, it is still a surgery and it is much safer (and prudent) to allow your tissues more time to heal, which takes more time than four days. Moreover, moving forward with a lower facelift is an investment and as such taking a few extra days to heal will only improve your chances for an excellent result. Years later the extra days you spent residing in one place and healing will seem inconsequential. Also, staying close to your surgeon is important because if minor issues arise they can be resolved quickly and without issue. I hope this helps.