After World War I, the unit was re-organized as a new organization, designated as the 2d Aero Squadron on 3 June 1919 at Rockwell Field, California.
A few days later, it was re-designated as the 2d Aero Squadron (Observation).
Many of the men were experienced mechanics and officers who had served either in France or at training units in the United States during World War I. After being organized, the squadron was transferred by train to San Francisco, California, where it boarded a ship bound for Manila, in the Philippine Islands, arriving on 24 December.
The squadron was assigned to the Philippine Department, and was stationed initially at Kindley Field, on Corregidor Island.
The squadron was equipped with some Curtiss HS2L and N-9 amphibian flying boats.

Initially attached to Post Headquarters, Fort Mills, it became part of the 1st Observation (later 4th Composite Group) on 10 March 1920.
The squadron's primary mission was coastal patrols and reconnaissance in and around the Manila Bay region.
It participated in exercises and maneuvers with Army ground forces and Naval forces were a regular and important part of its mission.
Another mission of the 2d Observation Squadron during the 1920s was aerial mapping of the Philippines, the topography of many of the islands were largely unknown.
On 8 April 1924, it was formally consolidated with its World War I and Philippines predecessor unit, giving the squadron a history dating to 1 December 1915.
As with other squadrons in the Philippines, the 2d received a wide variety of second-line hand-me-down aircraft transferred from units in the United States during the austere years of Air Corps procurement during the 1920s and 1930s.
It operated various Loening seaplanes, Dayton-Wright DH-4s, Thomas-Morse O-19s, Sikorsky and Douglas Dolphin amphibians, as well as other aircraft that the Army would send from the United States that it thought could be used in the Philippines.
In June 1929, the squadron was moved off Corregidor to the 4th Composite Group and Philippines Department Headquarters at Nichols Field, near Manila.

As a result of the rising tensions with the Japanese Empire in 1940, the defenses of the Philippines were judged to be abysmal, and a reinforcement effort was made to defend the islands against any Japanese aggression.
Although beginning in 1938, the Army sent some Douglas O-46 observation monoplanes, these were supplemented in 1941 with some new Curtiss O-52 Owls, and the squadron was moved to Clark Field on 1 November 1940.
In late 1941, the 4th Composite Group was broken up due to the expanding Air Corps presence in the Philippines.
The pursuit squadrons were assigned to the new 24th Pursuit Group and the 28th Bomb Squadron was assigned to the incoming 19th Bombardment Group.
The 2d Observation Squadron was reassigned directly to Far East Air Force (FEAF) headquarters as a courier and reconnaissance squadron, reporting to the Headquarters staff.
It was moved to Nichols Field on 1 November.
After World War I, the unit was re-organized as a new organization, designated as the 2d Aero Squadron on 3 June 1919 at Rockwell Field, California. A few days later, it was re-designated as the 2d Aero Squadron (Observation). Many of the men were experienced mechanics and officers who had served either in France or at training units in the United States during World War I. After being organized, the squadron was transferred by train to San Francisco, California, where it boarded a ship bound for Manila, in the Philippine Islands, arriving on 24 December. The squadron was assigned to the Philippine Department, and was stationed initially at Kindley Field, on Corregidor Island. The squadron was equipped with some Curtiss HS2L and N-9 amphibian flying boats.
Initially attached to Post Headquarters, Fort Mills, it became part of the 1st Observation (later 4th Composite Group) on 10 March 1920. The squadron's primary mission was coastal patrols and reconnaissance in and around the Manila Bay region. It participated in exercises and maneuvers with Army ground forces and Naval forces were a regular and important part of its mission. Another mission of the 2d Observation Squadron during the 1920s was aerial mapping of the Philippines, the topography of many of the islands were largely unknown. On 8 April 1924, it was formally consolidated with its World War I and Philippines predecessor unit, giving the squadron a history dating to 1 December 1915. As with other squadrons in the Philippines, the 2d received a wide variety of second-line hand-me-down aircraft transferred from units in the United States during the austere years of Air Corps procurement during the 1920s and 1930s. It operated various Loening seaplanes, Dayton-Wright DH-4s, Thomas-Morse O-19s, Sikorsky and Douglas Dolphin amphibians, as well as other aircraft that the Army would send from the United States that it thought could be used in the Philippines. In June 1929, the squadron was moved off Corregidor to the 4th Composite Group and Philippines Department Headquarters at Nichols Field, near Manila.
As a result of the rising tensions with the Japanese Empire in 1940, the defenses of the Philippines were judged to be abysmal, and a reinforcement effort was made to defend the islands against any Japanese aggression. Although beginning in 1938, the Army sent some Douglas O-46 observation monoplanes, these were supplemented in 1941 with some new Curtiss O-52 Owls, and the squadron was moved to Clark Field on 1 November 1940. In late 1941, the 4th Composite Group was broken up due to the expanding Air Corps presence in the Philippines. The pursuit squadrons were assigned to the new 24th Pursuit Group and the 28th Bomb Squadron was assigned to the incoming 19th Bombardment Group. The 2d Observation Squadron was reassigned directly to Far East Air Force (FEAF) headquarters as a courier and reconnaissance squadron, reporting to the Headquarters staff. It was moved to Nichols Field on 1 November.
2nd Air Refueling Squadron