The Niess 2-100, was a civilian two-seat high-wing sport aircraft built in Brazil during 1952.
It was developed and manufactured by Marc Niess, a Brazilian aeronautical engineer, while the certification tests for the Niess 1-80 were still underway. With a similar fuselage to its predecessor, it was distinguished by its tricycle landing gear and its negative-glare wings with forward-facing tips, which gave it advantages over stall. After some tests at the Parque Aeronáutico de São Paulo, some stability problems were noted, which were solved by increasing the rudder's vertical surface.
The first prototype was sent to the Department of Aerospace Science and Technology in São José dos Campos, where it underwent further tests with pilots from the Brazilian Air Force, where it was approved. The National Civil Aviation Agency of Brazil bought two airplanes, including the prototype. The first (PT-GLI) was deactivated after flying for five years.
Some years later, the second (PP-ZPE) was returned to Marc Niess, who took it to São Paulo, where it was stored until it was destroyed in an accident that occurred in the building it was in.