The size limitation is 62" in diameter. We just bought a suitcase that ended up being 65" in diameter. It is so light, perfect for packing for a year in Israel. Do you think they will let it pass? Are they usually strict about slightly oversized luggage. We will keep it under fifty pounds...
My daughter just flew AA from JFK to Israel and no one looked at the size of the luggage, only the weight. There were girls pulling out pieces of clothing to try to get to under 50 lbs., but I was in the check-in line with her and didn't hear or see anyone question the luggage size. Not exactly factual information, but wanted to share in case this helps.
As others have posted, size is only an issue if you want to bring on the plane.
For checked luggage, they just weigh it and toss it on the conveyor. I would imagine if one tried to check something that was immense, there would be an issue but they don’t have care about a few inches in the luggage hold.