The Nieuport 81 (Nieuport 23M) was the second in a series of two-seat trainers based on earlier Nieuport designs. It appears to be closely based on the Nieuport 12, although its wing area was one square meter larger. The aircraft had two separate cockpits with dual controls. The 110 hp Clerget engine was replaced by an 80 hp Le Rhône, which may explain the `80' series designation The A.E.F. Air Service purchased 173 Nieuport 81s.

The Nieuport 83 (Nieuport 18M) was the last in the line of two-seat trainers powered by the 80 hp Le Rhône engine. It had dimensions nearly identical to the Nieuport 80 and was probably a rebuilt Nieuport 10. The aircraft featured a communal cockpit of the Nieuports 10 and 82. The A.E.F. Air Service purchased 244 examples of the Nieuport 83 E2. The syllabus called for the student to graduate from the Nieuport 80 or 81 primary trainer to the Nieuport 83 E2.