In June 1941, Korobitzin was commanding officer of the 96 Otdelnaya Aviaeskadrilya (OIAE - independent squadron). In June 1941, the unit was based on Izmail airfield and equipped three Polikarpov I-153s and fourteen Polikarpov I-15bis.

During the Axis attack on Soviet Union in June 1941 Rumanian forces attacked the part of the front that included Izmail.

At 14:00 on 22 June 1941, fourteen I-15bis and three I-153s of 96 OIAE (the entire squadron) scrambled from their airfield at Izmail, alarmed by early warning on incoming enemy aircraft- They attacked eight Romanian I.A.R. 37 biplanes of Escadrila 18 bombardament at 1,000 meters over Izmail, close to the estuary of the Danube in southern Bessarabia, claiming five of them shoot down.
The 96 OIAE commander kapitan Korobitzin and starshiy leitenant Mikhail Maksimov (whose victim fell into the Danube River) each claimed a destroyed. A third was claimed by mladshiy leitenant Boris Maslov from starshiy leitenant Maksimov’s flight. One shared was claimed by starshiy leitenant Lavrentiy Borisov, deputy commander of 96 OIAE, and leitenant Nikolay Cherkasov. The fifth, finally, was claimed as a shared between leitenant Vasiliy Kuroedov (flight commander), leitenant Leonid Khomutov, leitenant Aleksandr Evstigneyev and leitenant Shota Gogmachadze.
In fact, only one I.A.R. 37 was shot down by Soviet fighters, most probably by mladshiy leitenant Maslov while a second was claimed by the 463rd Anti-Aircraft Battery under starshiy leitenant G. Okhota. Maslov returned to base much later than his colleagues on his last drops of fuel. He had pursued an enemy aircraft way behind the line of the Danube until finishing it off deep inside enemy territory. Upon return, ground crew could count many bullet holes in the airframe of Maslov’s I-15bis.
The Rumanian biplanes, which lost two of their numbers, had been escorted by eight He 112B from Grupul 5 Vânatoare.

Korobitzin ended the war with 1 biplane victory.

Claims:

Kill no.	Date	Time	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1941
1	22/06/41	14:00	1	I.A.R. 37 (a)	Destroyed	I-15bis (b)		Izmail area	96 OIAE

Biplane victories: 1 destroyed.
TOTAL: 1 destroyed.
(a) Claimed in combat with I.A.R. 37s from Escadrila 18 bombardament, which lost 2 aircraft (1 to AA fire). 96 OIAE claimed 5 destroyed without losses.
(b) This victory may have been claimed while flying I-15bis or I-153s.

Sources:
From Barbarossa to Odessa: Volume 1 – Dénes Bernád, Dmitriy Karlenko and Jean-Louis Roba, 2007 Ian Allan Publishing Ltd, ISBN 978-85780-273-3
Heinkel He 112 in action - Dénes Bernád, 1996 Squadron/Signal Publications, Carrollton kindly provided by Ondrej Repka
Morskie letchiki v oborone Odessy - A.P. Dorokhov, 1982 Mayak, Odessa, kindly provided by Yuri Shakhov
Rumanian Air Force: The Prime Decade, 1938-1947 - Dénes Bernád, 1999 Squadron/Signal Publications, Carrollton, ISBN 0-89747-402-3
Sovetskaya aviacia nad morem - Sergey Bogatyrev, 1999 Aviacia i Vremya 3/99, Ukraine kindly provided by Ondrej Repka
Vtorzhenye, part III - Dmitriy Khazanov, 1996 Aviacia i Vremya 5/96, Ukraine kindly provided by Ondrej Repka
Additional information kindly provided by Mirek Wawrzynski