I would like to know too, but I think you should be ok. I doubt they're going to know that it's 1 cm over. My suitcase is also 28 inches. I usually bring that and a backpack. I haven't had any issues with AC, WS, TK, HX, CX, UA, DL, and VN. These are the airlines that I've flown over the past 12 months. Don't think I'm missing any. I just booked a flight with ANA to HND, but I won't be flying until later this spring. I might have to go with a 24" if you have a negative experience checking-in your 28".