When the Spanish Civil War begun Carlos Bayo Alessandri served as a machine-gunner/bomber in the Córdoba Breguet XIXs, where he remained until spring 1937.

He then went to Pilots’ School and from there he was posted to the He 51 group.

He joined 2-G-3 in November 1937. This unit was equipped with the Fiat CR.32.

On 28 December 1937, 16 fighters from Grupo 2-G-3 clashed with nine I-15s and 12 I-16s directly above Teruel. Nationalist pilots were credited with shooting down four ‘Curtiss fighters’ and a Rata for the loss of Antonio López Sert (3-87) of Escuadrilla 1-E-3 (reportedly to small-arms fire). Teniente Bayo (2-E-3) attacked a Chato head-on, scoring some hits. He made a second attack from astern and the enemy fighter began to lose height and crashed behind Republican lines near Villastar. Alférez Javier Allende Isasi (2-E-3) claimed two I-15s while alférez Jorge Muntadas Claramunt (2-E-3) claimed the fourth I-15 and alférez Manuel Vázquez Sagastizábal (1-E-3) claimed the I-16.
It seems that at least the 3^a/26 (I-15) was involved in this combat and they claimed four CR.32s during the day. The CO of the unit, teniente Juan Comas Borrás claimed two CR.32s while sargento Francisco Montagut Ferrer and Rafael Sanromá Daroca claimed one each.
The Republicans admitted the loss of teniente José M.^a Campoamor Peláez, who fell with his burning I-15 in the vicinity of La Muela, while two other aircraft returned to base damaged.

In the afternoon of 6 January 1938, teniente Manuel Vázquez Sagastizábal and teniente Bayo from 2-G-3 went to the defence of a unit of He 111s that was being attacked by enemy fighters. Vázquez attacked the lower group hitting a Chato, which fell in flames to the east of Teruel, while Bayo was successful in destroying a second Chato.

At 08:00 on 29 January, Miguel García Pardo and teniente Bayo spotted Russian tanks moving to attack Nationalist positions at Cabezón, in the Singra sector. They attacked these at low level with machine-gun fire, and shortly after found eleven more tanks attacking to the east of Celadas. Returning to base their ammunition exhausted, they located five tanks on the plain near Singra, with five more behind them.

In March 1938, the Group took part in Aragón offensive.

In the afternoon on 12 March, 2-G-3 encountered enemy aircraft attempting to stop the sweeping advance in the Aragon offensive. During the afternoon 18 Fiats, led by capitán Ángel Salas (CO) and capitán Joaquín García Morato, escorted Ju 52/3ms on a raid, and having completed this task made a sweep of the front as far as Híjar, where they encountered 19 Chatos that were escorting 11 SBs. In the ensuing dogfights, capitán Salas claimed one probable I-15, capitán Morato claimed two I-15s while teniente Miguel García Pardo (2-E-3) destroyed one I-15, which fell near Híjar. Teniente Miguel Guerrero García (1-E-3) set fire to another I-15, whose pilot took to his parachute from a very low height. Teniente Julio Salvador (CO 1-E-3) attacked another machine, which began to trail smoke, but he was unable to continue his attack as his Fiat was almost out of fuel; unable to return to his base at Tauste, he had to land at Saragossa. Teniente Carlos Serra Pablo-Romero, teniente Bayo (2-E-3) and teniente Rodolphe de Hemricourt (2-E-3) each were successful in shooting down an I-15. Teniente Manuel Vázquez Sagastizábal (1-E-3) attacked three SBs claiming one of them that crashed while attempting to land near Escatrón. No CR.32s were lost in this combat.
The I-15 shot down by teniente García Pardo was from 1^a/26 and was flown by Soviet pilot starshiy leitenant Bela Arady, who bailed out badly burned and landed in Republican lines. The wreckage of this machine (I-15 CA-057) was recovered subsequently, and a piece of it was retained, on which ensuing victories of 2-G-3 were recorded, as well as the names of all those in the group who were killed.

On 4 May, Commander Ángel Salas of 2-G-3 had his fuel and water tanks holed by machine-gun fire from the ground, forcing him to make an emergency landing at Aguilar aerodrome, which had been occupied only days before. During the same sortie the Fiats flown by Bayo, Jorge Muntadas Claramunt and de Hemricourt all received damage from ground fire.

In the morning on 14 August, Grupos 2-G-3 and 3-G-3 attacked a formation of Ratas, which were pursuing some He 111s over Gandesa. Other Chatos and Ratas later joined in the battle. Totally the Spanish pilots reported 52 I-16s and 28 I-15s (!).This massive formation of Polikarpovs was also targeted by ten Bf 109s.
Group 2-G-3 claimed three Ratas (teniente Miguel García Pardo (2-E-3), Bayo (2-E-3) and teniente de Hemricourt (2-E-3)) and 3-G-3 claimed two more (comandante Joaquín García Morato and teniente Emelio O’Connor Valdivielso (4-E-3)). 2-G-3s record of operations described the combat:

“García Pardo attacked some Ratas which were pursuing an He 111, shooting down one of the which fell near to Mora de Ebro … Teniente Bayo attacked three Ratas and succeeded in destroying one which fell on the edge of the Blanerías mountains. Later he attacked a Chato, but was unable to ascertain whether it was destroyed as damage to his engine forced him to land at Horta…
Teniente de Hemricourt fired at one Rata without any result; and then attacked some Ratas engaged with other Fiats, hitting one which fell in a wood to the north of Reus.”

In the morning on 2 September, a formation of nine R-Zs, escorted by a similar number of I-15s, were attacked by 18 Spanish-flown CR.32s near Monterrubio de la Serena as they returned from a bombing mission. Minutes later nine SBs from 4^a Escuadrilla of Grupo N^o 24, escorted at a distance by 11 I-16s Type 10, hove into view too. The CR.32s concentrated on the Tupolev bombers and their monoplane fighter escorts. In a single attack, capitán Ángel Salas (2-G-3) destroyed three Katiuskas, and then capped this by damaging the I-16 Type 10 flown by the leader of the 1^a Escuadrilla Grupo de Moscas N^o 21 that was escorting them. This pilot, teniente José Redondo Martín (the son of the former mayor of Madrid, Cayetano Redondo Aceña), took to his parachute and was guarded by Salas until he had almost reached the ground. Salas, before flying away, raised an arm in the Fascist salute, and Redondo (I-16 ‘CM-214’) responded in a similar manner with a clenched fist.
Salas noted in his logbook:

“After 50 minutes on patrol I spotted nine “Martin bombers” that were a little higher than us heading in the direction of our lines. I gained height as I flew towards them, cutting off their escape route. As they returned after bombing Monterrubio, I attacked the bomber on the left in the first section, setting his left engine on fire. I then hit the left engine of the leader’s aircraft, setting it on fire too, and the third bomber suffered the same fate. Then I fired straight up at the leader of the second flight, and his aircraft started trailing white smoke. It was then that I noticed some Ratas, so I attacked one. After a long fight it also started to trail smoke, and the pilot took to his parachute. He landed close to his aircraft, north of Belalcázar. During his descent I saluted him and he saluted me back.”

“The part played by the group under your command in today's operation has filled me with pride and it gives me great satisfaction to have people under my command who know how to make the best use of prevailing circumstances. It gives me great pleasure to congratulate you personally, and the whole of your unit, to whom I hope you will convey this message.”

On 20 September a series of daily battles began, culminating in fierce combats on 2 and 3 October. Groups 2-G-3 and 3-G-3 fought jointly in all these battles, achieving a total of twenty-five victories (17 by 2-G-3). Of these Bayo claimed four.

On 15 October 1938, four squadrons of Fiats made a combined sortie, three from 2-G-3, and one from 3-G-3. They succeeded in destroying two Ratas (Bayo and González Guzmán), one for each group. Capitán Ángel Salas, Manuel Vázquez Sagastizábal and Bayo each damaged another.

The battle of the Ebro ended in the middle of November and after this Bayo was transferred to 5-G-5, which was equipped with German monoplanes (Bf 109s and He112s). Bayo, however, didn’t claim anything while flying in this unit.

After the end of the war he was decorated with the Cruz Militar (the Military Medal) and promoted for his services during the war. The medal was however not presented to him until the day of Our Lady of Lareto in 1941, by which time he was involved in a new war!

Bayo ended the Civil War with 11 biplane victories (and 1 probably destroyed) of which six were I-16s and five were I-15s.

He later volunteered for combat in Russia and was part of the 1^a Escuadrilla Azul, (Escuadrilla Expedicionaria) which was formed with 17 pilots with Salas as the Commander. Some of them were veterans of the Spanish Civil War and had a combined score of 79 aerial victories.

The unit crossed into France on 24 July 1941, later arriving in Germany in late part of the month.

They were assigned to training at the Jagdfliegerrschule 1 at Werneuchen near Berlin.

After completing their training on Bf 109 Es, the 1^a Escuadrilla left for Russia on 26 September.
At first the Spanish pilots were worried that they would arrive late to see any action, since they were kept informed of the progress of the German advance towards Moscow.

Azul Escuadrilla is welcomed on the East Front at Moschna airfield in September 1941.

The 1^a Escuadrilla received a total of 12 Bf 109 E-4s and –7s and they were assigned to JG 27, VIII FliegerKorps of LuftFlotte 2. They were known as the “15 Spanische Staffel”, and they started to fly their first combat operations on 2 October. Escorting German bombers and reconnaissance aircraft, they operated from 12 different airfields.
Already on the first day, 2 October, they suffered their first pilot causality, when Luis Alcocer (Bf 109 E-7 WNr. 1390) was shot down and killed in air combat with MiG-1s, I-16s and Il-4s 6 kilometres north of Moschna.

On 7 October, the Escuadrilla undertook 42 sorties and in the course of the day, Commendante Ángel Salas Larrazábal shot down an “I-18” for his third personal and unit victory while Captain Bayo claimed a damaged MiG-3.

On 13 October, Captain Bayo claimed an I-18 while Lieutenant Esteban Ibarreche Arriaga claimed a biplane.

On 14 October, Salas in the company with three other pilots in a “free hunt” near Kalinin surprised three DB-3 bombers. In the resulting combat Salas claimed two, while Captain Bayo destroyed the third DB-3, but during the heat of the combat Salas and Bayo collided resulting in Salas Bf 109’s rudder being partially destroyed but he made it back to base.

Bayo claimed a DB-3 on 17 October (alternatively on 18 October).

The 1^a Escuadrilla Azul received the orders to return to Spain on 6 January 1942.
During their time in Russia the unit flew a total of 460 missions, were engaged in 94 aerial combats and destroyed 10 enemy aircraft plus four on the ground, for the loss of 5 pilots (one KIFA, three MIA and one KIA) plus one wounded in action.
Bayo totally claimed 3 victories and 1 destroyed on the ground during his time in Russia.

Carlos Bayo ended the war with 11 biplane victories and a total of 14. All of the biplane victories were claimed during the Spanish Civil War.

Bayo passed away on 1 February 1979.

Claims:

Kill no.	Date	Time	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1937
1	28/12/37		1	I-15 (a)	Destroyed	Fiat CR.32		Teruel	2-E-3
	1938
2	06/01/38	p.m.	1	I-15	Destroyed	Fiat CR.32		E Teruel	2-E-3
3	12/03/38	afternoon	1	I-15 (b)	Destroyed	Fiat CR.32		Híjar	2-E-3
4	14/08/38	morning	1	I-16 (c)	Destroyed	Fiat CR.32	3-127	Blanerías mountains	2-E-3
	14/08/38		1	I-15 (c)	Damaged	Fiat CR.32	3-127	Blanerías mountains	2-E-3
5	02/09/38	morning	1	I-16	Destroyed	Fiat CR.32		Zújar area	2-E-3
6	15/10/38		1	I-16	Destroyed	Fiat CR.32			2-E-3
	15/10/38		1	I-16	Damaged	Fiat CR.32			2-E-3
7	??/??/38		1	I-16	Destroyed	Fiat CR.32			2-E-3
8	??/??/38		1	I-16	Destroyed	Fiat CR.32			2-E-3
9	??/??/38		1	I-16	Destroyed	Fiat CR.32			2-E-3
10	??/??/38		1	I-15	Destroyed	Fiat CR.32			2-E-3
11	??/??/38		1	I-15	Destroyed	Fiat CR.32			2-E-3
	??/??/38		1	I-16	Probably destroyed	Fiat CR.32			2-E-3
	1941
	07/10/41		1	MiG-3	Damaged	Bf 109 E		Russia	1a Escuadrilla Azul
12	13/10/41		1	I-16	Destroyed	Bf 109 E		Russia	1a Escuadrilla Azul
13	14/10/41		1	DB-3 (d)	Destroyed	Bf 109 E		Kalinin area	1a Escuadrilla Azul
14	17/10/41		1	DB-3 (e)	Destroyed	Bf 109 E		Russia	1a Escuadrilla Azul
	??/??/41		1	Enemy aircraft	Destroyed on the ground	Bf 109 E		Russia	1a Escuadrilla Azul

Biplane victories: 11 destroyed, 1 probably destroyed, 2 damaged.
TOTAL: 14 destroyed, 1 probably destroyed, 3 damaged, 1 destroyed on the ground.
(a) Grupo 2-G-3 claimed 4 I-15s and 1 I-16 for the loss of 1 CR.32. The Republicans claimed 4 CR.32s while losing 1 I-15 and 2 damaged.
(b) 2-G-3 claimed 7 I-15s, 1 probable and 1 damaged and 1 SB destroyed without losses. Republican losses is not known.
(c) Claimed in combat with I-16 from 1^a, 3^a and 4^a Escuadrillas which lost at least one I-16 and got three more damaged while claiming 3 CR.32s and 1 He 111. 2-G-3 claimed three I-16s and 3-G-3 claimed two more while losing one CR.32 and getting 3 more damaged.
(d) According to German sources this was claimed as an SB-3.
(e) According to German sources this was claimed on 18 October 1941.

Sources:
Air War over Spain - Jesus Salas Larrazabal, 1974 Ian Allan Ltd, Shepperton, Surrey, ISBN 0-7110-0521-4
Angel Salas Larrazabal - A Fighter Ace in Two Wars (WWII Ace Stories) - Santiago A. Flores, 2001
Deutsche Luftwaffe Losses & Claims -series - Michael Balss
Fiat CR.32 Aces of the Spanish Civil War - Alfredo Logoluso, 2010 Osprey Publishing, Oxford, ISBN 978-1-84603-983-6
Några leva än - F. G. Tinker, 1939 T. V. Scheutz Bokförlag AB, Stockholm
Spanish Republican Aces – Rafael A. Permuy López, 2012 Osprey Publishing, Oxford, ISBN 978-1-84908-668-4
The Facile Fiat...Rosatelli's "Italian Fighter" - Air Enthusiast/Twenty-Two
The Legion Condor - Karl Ries and Hans Ring, 1992 Schiffer Publishing, ISBN 0-88740-339-5
Additional information kindly provided by Christer Bergström, Ondrej Repka and Tom Semenza.