Flown in one of those before, SFC Joe S. Davis Jr., MSM, DSL!

Thank you my friend SFC Joe S. Davis Jr., MSM, DSL for sharing this image of Cessna O-1 Bird Dog (L-19) Liaison / Observation STOL Aircraft

Background from militaryfactory.com/aircraft/detail.asp?aircraft_id=751#specs
"SPECIFICATIONS
Unless otherwise noted the presented statistics below pertain to the Cessna O-1 Bird Dog (L-19) model. Common measurements, and their
respective conversions, are shown when possible.
CREW: 2
LENGTH: 25.75 feet (7.85 meters)
WIDTH: 35.99 feet (10.97 meters)
HEIGHT: 7.28 feet (2.22 meters)
WEIGHT (EMPTY): 1,614 pounds (732 kilograms)
WEIGHT (MTOW): 2,401 pounds (1,089 kilograms)
ENGINE: 1 x Continental O-470-11 six piston engine developing 213 horsepower.
SPEED (MAX): 130 miles-per-hour (209 kilometers-per-hour; 113 knots)
RANGE: 530 miles (853 kilometers; 461 nautical miles)
CEILING: 20,341 feet (6,200 meters; 3.85 miles)
RATE-OF-CLIMB: 1,040 feet-per-minute (317 meters-per-minute)
HISTORY
Detailing the development and operational history of the Cessna O-1 Bird Dog (L-19) Liaison / Observation STOL Aircraft. Entry last updated on 9/7/2018.
In 1947, the United States Army Air Forces ceased to exist in the American military structure, replaced instead by two autonomous entities in the United States Army and the United States Air Force (USAF). This left the United States Army without its own dedicated air support wing which was still required in fulfilling various battlefield roles including light scout, liaison, artillery spotting and observation. Following the events of World War 2 (1939-1945) a very robust product was now envisioned revolving around use of all-metal skin. The U.S. Army then put forth a requirement for a new two-man, single-engined platform capable of short-field/rough-field operations with excellent handling at low altitudes and equally-excellent vision out-of-the-cockpit. Taking their Model 170 as a starting point, the Cessna concern entered their Model 305A into the competition.
The Cessna design incorporated a conventional aircraft arrangement with the engine fitted to a compartment at front and a single-finned tail unit at rear. The undercarriage was simplistic yet rugged, made up of a pair of single-wheeled main landing gear legs and a small tail wheel.
The whole undercarriage was non-retractable which further aided in simplicity and kept procurement and maintenance costs in check. The engine drove a two-bladed propeller assembly at front while the cockpit utilized a tandem-seating (inline) arrangement for the two crew and all sides of the compartment were windowed for maximum viewing. To further improve on a largely unobstructed view, the straight monoplane wing assembly was sat upon the top of the cabin and this also gave good lifting qualities and strong handling at low speeds.
Indeed pilots soon learned they could simply "float" their Model 305s "in space" without stalling and land with very little runway distance ahead. Struts emerging from the lower fuselage sides ran upwards to each wing underside for added strength and support of the flexible structure.
First flight of the Model 305 occurred on December 14th, 1949 with the end result being a U.S. Army contract. The aircraft was formally accepted into service as the L-19A "Bird Dog" with introduction set for December of 1950. The "Bird Dog" name was provided by Cessna through an employee contest and referenced hunting dogs used by masters to help identify possible game.
Due to the growing American commitment in the Korean War (1950-1953), the Bird Dog was immediately pressed into service in the conflict as soon as usable numbers became available. The American military went ahead with a 3,200-strong order of the small, agile aircraft and
manufacture of these aircraft spanned from 1950 into 1959. Eventually they stocked both U.S Army and USMC air wings and their roles broadened from general liaison and observation service to more harrowing MEDEVAC, artillery spotting and airborne communication relay roles. In 1953, an instrument trainer variant was developed and hurried placed into production to serve new generations of Bird Dog flyers and spotters. The Korean War can to an uneasy cease-fire in 1953 though Bird Dog use continued.
From the period of 1955 to 1975, the conflict in Vietnam brewed and eventually grew the American commitment in that part of the world. As a result, the Bird Dog was back in play for its multi-role capabilities and the USAF now took interest in the mount for the Forward Air Control (FAC) role. FAC was utilized to provide direction for Close-Air Support actions assisting ground "friendlies". In this way, the little aircraft could relay pertinent information to incoming strike aircraft and (hopefully) avoid friendly casualties while laying waste to nearby enemies.
During the war, the Bird Dog faithfully served in the communications, spotting, scouting and other like-roles which further solidified the diminutive aircraft's forte in a combat zone. Air-to-surface rocket tubes were affixed under the wings to provide a limited offensive punch when needed. Nearly 500 Bird Dogs were lost during the war. Ex-American Bird Dogs were passed to the South Vietnamese Air Force and additional service during the war came from several Australian Army-directed Bird Dogs.
Bird Dog operators proved plentiful and reached Cambodia, Canada, France, Indonesia, Italy, Japan, Norway, Pakistan, Spain, Taiwan and
Thailand among many others (see operators listing for full report). Japanese military stocks were strengthened through local license production of the aircraft under the Fuji brand label and Italian Army versions were delivered as the SM.1019 with local production by SIAIMarchetti.
Total Bird Dog production eventually reached an impressive 3,431 aircraft during a very lengthy career worldwide.
Bird Dogs were gradually being replaced across all major branches of service in the American military heading into the 1970s - the final frontline example was retired in 1974. Despite this, civilian-governed models have still soldiered on into the new millennium and have remained popular with owners. The similar Model 325, based on the Model 305, is another notable form and used in the agricultural spray business.
Designations of the Bird Dog line included the original L19A used by the U.S. Army of which 2,486 were eventually produced. These were then redesignated as O-1A in the 1962 U.S. military designation reorganization. TL-19A signified dual-control trainer versions which became TO-1A in 1962. 310 TL-19D instrument trainers were produced and became the TO-1D. The L-19E was an improved L-19A with increased gross weight, becoming the O-1E in 1962 and seeing production reach 469 examples. OE-1 were 60 original USMC Bird Dogs in the L-19A standard, becoming the O-1B in 1962. The OE-2 was the OE-1 but with Cessna Model 180 wings and a revised fuselage. These were
redesignated to O-1C in 1962 and saw production total 27 examples. The O-1D line were TL-19D trainers modified for the Forward Air Control (FAC) role with the USAF. The O-1F followed suit and was based on the O-1D while the O-1G was the O-1A of the USAF for use in FAC.
The XL-19B was a "one-off" experimental Bird Dog with a Boeing XT-50-BO-1 turboprop engine of 210 horsepower. Similarly, the XL-19C existed as two prototype Bird Dogs outfitted with Continental CAE XT51-T-1 turboprop engines of 210 horsepower. None were furthered in serial production.
The typical Bird Dog (taking the O-1E as an example) design was powered by a Continental O-470-11 six piston engine developing 213 horsepower. This supplied the design with a maximum speed of 130 miles per hour, a range out to 530 miles, a service ceiling of 20,300 feet and a rate-of-climb of 1,040 feet per minute. Dimensions included a length of 25 feet, 9 inches, a wingspan of 36 feet and a height of 7 feet, 3 inches. Empty weight was 1,600lbs with a Maximum Take-Off Weight (MTOW) of 2,800lbs being reported."

Flying in Vietnam US ARMY Cessna O 1 L19 Bird Dog pilot
https://www.youtube.com/watch?v=Sco7cZ4SoMc


FYI COL Mikel J. Burroughs LTC Stephen C. LTC (Join to see) Lt Col John (Jack) Christensen Lt Col Charlie Brown Maj Bill Smith, Ph.D. Maj William W. 'Bill' Price Maj Marty Hogan SCPO Morris Ramsey SGT Mark Halmrast Sgt Randy Wilber Sgt John H. SGT Gregory Lawritson CPL Dave Hoover SPC Margaret Higgins SSgt Brian Brakke 1stSgt Eugene Harless CPT Scott Sharon PO1 H Gene Lawrence

SFC Joe S. Davis Jr., MSM, DSL Are these still in service.