The Cessna L-19 Bird dog, a two-seater powered by a 190 hp Continental engine, is a observation aircraft that played a significant role for the US Army during the 1950's and '60s. Designed as a liaison aircraft to replace the L-4 Cubs and L-5 Stinsons of WW-II, the L-19 played a significant role in both the Korean and Vietnam conflicts.

 

Info from http://www.classicfighters.co.nz/aircraft/birddog.htm