In aviation , the undercarriage or landing gear is the structure -LRB- usually wheels , but sometimes skids , floats or other elements -RRB- that supports an aircraft on the ground and allows it to taxi .

In aviation , the undercarriage or landing gear is the structure -LRB- usually wheels -RRB- that supports an aircraft and allows it to move across the surface of the LOCATION@1 when it is not flying .
