The smallest tactical unit of the german Luftwaffe was the Rotte. It consisted of two planes. In a "Rotte" the task of the second pilot - also called the "Katschmarek" - was to give cover to his leader during the combat.
An unit, consisting of two "Rotten", was called "Schwarm". This formation was developed by the germans and successfully used for the very first time during the Spanish Civil War. The positions of the planes in this "Schwarm"-formation were established in a way, that gave the formation a perfect view to all directions.
The "Staffel" normaly
consisted of 3 "Schwärme". So a "Staffel" had about 12 planes. The
leader, the "Staffelkapitän", mostly was an "Oberleutnant" (1. Lieutenant)
or a "Hauptmann" (Captain).
The Luftwaffe "Staffeln"
were marked with arabic numbers (e.g. "1. Staffel").
For identification
the planes of each Staffel were numbered from one to x. Each Staffel of
a "Gruppe" had numbers on the fuselage with an own colour. White numbers
were the "Staffeln" 1, 4, 7 and 10, red nubers were the planes of "Staffeln"
2, 5, 8, 11 and yellow the "Staffeln" 3, 6, 9 and 12.
The "Gruppe" normally
consisted of 3 "Staffeln" and a "Stabsschwarm" (staffschwarm). This gave
the "Gruppe" about 40 planes. The "Gruppe", mostly leaded by a Major,
was written with roman numbers (e.g. "II. Gruppe").
To identificate
a "Gruppe" plane, all Luftwaffe day-fighters got a special mark on the
fuselage.
The biggest, transferable
unit in Luftwaffe consisted of 3 or 4 "Gruppen". So the "Geschwader" got
about 120 planes. The leader of the "Geschwader" was from the rank Major
or more.
The "Geschwader" was written with arabic numbers (e.g. "Jagdgeschwader 51", shorter "JG
51").
Luftwaffe "Geschwader"also got different marks. Each "Geschwader" had it´s own
emblem, mostly attached to the cockpit´s or engine´s side. Later in war the
"Jagdgeschwader" aircrafts got individial coloured marks (in form of tail-bands)
around the fuselage.
The expression "I./JG
27" is the short form for "1. Gruppe of Jagdgeschwader 27".
"3./JG 27" is the
abbreviation of "3. Staffel of (1. Gruppe) Jagdgeschwader 27".