One of the pilots from the Grasshoppers team survived by ejecting with a parachute, according to local media reports. Police would only confirm the death.
According to the Basellandschaftlichen Zeitung newspaper, the collision happened as the planes were executing a curve in a formation of three aeroplanes, when one plane touched the other's tail.
One of the aeroplanes crashed into a barn in the nearby town of Dittingen. The show had been at the town's airfield, near Basel.
According to the Grasshoppers' Facebook page, its three aeroplanes are all Icarus C42s. Formed in 2011, the southern group likes to show off "the entire bandwidth" of the possibilities of the ultra-light vessel.