Most dining tables are designed to come apart, and removing the legs is the whole game. A tabletop travels flat or on edge and takes up far less space than the assembled table.
Pro tip: Bag and tape the leg bolts to the underside of the tabletop so the hardware travels with the piece it belongs to.
Watch out: Do not carry a table by its legs when assembled, since the leg joints are a common failure point and can snap off.