Here is what came up on Google.
What is the biggest bag you can check on a plane?
The maximum number of linear inches on a checked bag for most airlines is 62 inches. This means that when you add up the length, width and height of the luggage you intend to check, it should not be more than 62 inches. Most standard suitcases, garment bags and duffel bags measure 62 linear inches or less.
I've been flying to Muncie and back for the last five years. They always look inside the box and are not always careful. I haven't seen them measure my travel box but it is within a half inch of being exactly 62". The controlling dimension (for me) is the length of the fuselage, and it fits diagonally in the box. Wings are about 28" and will fit with the flaps.
As far as I know you can check larger items for a phenomenal fee.