Updated

The following is a quick look at the organization of the U.S. Air Force:

Overview

• The U.S. Air Force is composed in its entirety of the regular Air Force, the Air National Guards and the Air Force Reserve. The Air Force currently includes eight major commands.
• The Air Force boasts an enlisted force of 288,720 under the command of 69,466 officers.

Leadership

Secretary of the Air Force: The civilian head of the Air Force is appointed by the president with Senate approval. The secretary is responsible for the formulation and implementation of Air Force policies consistent with the national security plan. The secretary reports to the Secretary of Defense, but has no command authority.
Chief of Staff of the Air Force: The top uniformed position in the Air Force, the chief of staff is a member of the Joint Chiefs of Staff and is responsible for the general readiness of the US Air Force. The chief of staff has no direct command authority.

Air Force Organization

Major Command: The top level and largest combat organization of the Air Force is the command, which is usually made up of three or more numbered air forces.
Numbered Air Forces:  These formations include two or more wings and are usually grouped with auxiliary units. Numbered air forces conduct operations with assigned and attached forces under a command
Wings: The basic unit for generating and employing combat capability. Wings normally operate the same type of aircraft, although composite wings do exist. This formation is the prime war-fighting instrument.
Group: This formation usually consists of two to four squadrons and a group headquarters.  All squadrons in a particular group fly the same type of plane, and they are referred to by type of plane (heavy bomber group, fighter group, etc.).
Squadron: Squadrons are not designed to conduct independent operations; they work in coordination with other units to conduct operations. A squadron usually consists of two or more flights.
Flights: A flight consists of two or more airplanes. In combat, this formation usually consists of four or more planes that fly in pairs, trios, or fours. One plane, the flight leader, contains the flight commander who directs flight operations.

Source: Jane's, Defenselink.mil, Global Security.org