Sure. Some patients travel to have their surgery and fly home shortly afterwards so you should be ok flying at 14 wks. It may not be the most comfortable trip you've ever taken but it can be safe IF you prepare ahead of time and take a couple of precautions. If your flight is longer than an hour or so, prepare to get up and walk around every hour. Do your ankle pumps like you did in physical therapy. This is to prevent you from getting DVT [deep vein thrombosis] which can be painful (and even fatal if a clot goes from your leg to your lungs). To make it easier to get up frequently, ask for an aisle seat. You might also want to wear your anti-embolism stockings (if you were given these to wear after surgery). If you have none, you might consider buying a pair of knee-high support stockings. I still wear them on long flights even though my hip replacements are 5 years old. And, yes, I still do ankle pumps and try to at least stand up every hour or so.
Of course it never hurts to ask for your surgeon's advice if you are uneasy with flying at this stage in your recovery.
Have had both hips replaced.