[Larry deZeng]

Erla
There were at least 7 of these, but I only located these two:

Identified Frontreparaturbetriebe (Arabic Numbers):

Frontreparaturbetrieb GL 2551 (Erla VII)
Formerly Frontreparaturbetrieb GL Antwerpen. Overhauled and repaired Bf 109 and Fw 190 fighter airframes; Mar 42 had 127 Germans plus 2,660 civilian employees; remained in operation in Antwerpen (Antwerp)/Belgium until at least 24 Aug 44, then withdrew to Germany and disbanded. (FpN: L 19583).

Frontreparaturbetrieb GL 2552 (Erla VI)
Mar 42 in Brussels – overhauled airframes; had 65 Germans and 984 civilian employees. Aug/Sep 44 withdrew to Germany and disbanded. (FpN: L 51273).

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Fliegersonderkommando Ob.d.L.

also as: Fliegersonderkommando d. Ob.d.L. (L.P.) Jüterbog

Perhaps the least known and most misleading of all the “Sonderkommandos”, Fliegersonderkdo. Ob.d.L. was the administrative unit for Luftwaffe personnel assigned or attached to manufacturers as test pilots, ferry pilots and for related purposes. It seems to have been little more than an office or orderly room with a couple of clerks and an NCO or an officer. It was first noted in official documents dated March 1943 with location at Jüterbog, but in October 1943 several paybooks (Soldbücher) taken from prisoners have entries placing it in Dedelstorf on both 7 and 23 October. Designated Fliegersonderkommando OKL from June 1944, it was still in existence in March 1945.

L. deZ.