Pitcairn PA-4 Fleetwing II
The Pitcairn PA-4 Fleetwing II, also called the Pitcairn Fleetwing DeLuxe, and the Pitcairn PA-4 Fleetwing is a commercial mail hauling and passenger biplane. == Design and development == Ten PA-4s were built before it was re-engined with the Wright J-5 Whirlwind as the Pitcairn PA-5 to fly on the CAM-19 mail routes.
Source: Wikipedia — Pitcairn PA-4 Fleetwing II (CC BY-SA 4.0)