| William Portwood Erwin | |
| Birth Date: | 18 October 1895 |
| Death Date: | (disappeared) |
| Birth Place: | Ryan, Oklahoma, USA |
| Death Place: | Pacific Ocean |
| Nickname: | Bill |
| Allegiance: |  United States |
| Branch: | Air Service, United States Army |
| Rank: | Lieutenant |
| Unit: | Air Service, United States Army |
| Battles: | World War I |
| Awards: | Distinguished Service Cross, French Croix de Guerre |
Lieutenant William Portwood Erwin (18 October 1895 – 19 August 1927) was an American World War I flying ace credited with eight aerial victories.[1] On 19 August 1927, he disappeared during the Dole Air Race from Oakland, California to Hawaii.
William Portwood Erwin was the son of W. A. Erwin of Chicago.[2] The younger Erwin, born elsewhere, was raised primarily in Chicago. Two sources claim he was born in Amarillo, Texas.[1] [3]
See also: Aerial victory standards of World War I.
Erwin was assigned to the 1st Aero Squadron on 19 July 1918. As a Salmson 2A2 pilot, he scored his victories between 15 September and 22 October 1918; half of them were with gunner Arthur Easterbrook.[3]
Erwin is believed to have died during the Dole Air Race between Oakland, California, and Hawaii.[3] He flew the Dallas Spirit, a custom aircraft built by the Swallow Airplane Company on credit for the attempt. Erwin failed to return from a search for two other missing competitors, the Miss Doran and The Golden Eagle, and is presumed drowned 19 August 1927.[4]