Roberto Alonso Santamaría was born in Saragossa on 31 January 1908.

In 1929 he enrolled at the Farman flying school at Toussus-le-Noble, in France, where he gained his private pilot's licence in June of that year.

Alonso Santamaría volunteered for the Aviación Militar six months later and was posted to Tablada airfield, Seville, with the rank of private.
Holding a pilot’s licence enabled him to apply for the military flying course, and he subsequently gained his wings on 22 October 1930.

In 1931 Alonso Santamaría was posted to the 4^o Batallón de Aviación deployed in the Spanish Moroccan protectorate, where he joined an escuadrilla based at Larache airfield.
On 14 November he was posted to Grupo de Caza N^o 13 of Escuadra N^o 3 in Barcelona.

On 30 January 1932, Alonso Santamaría was told to fly Ni-H.52 ‘3-6’ from Getafe to Barcelona, but engine trouble resulted in him force-landing at Morata de Jalón, Saragossa.
The same year, he qualified as an air gunner- bombardier at Los Alcázares airfield, and he was promoted to the rank of cabo in October 1933.

On 30 May 1935, he flew with his unit to Barajas airfield, Madrid, where, on 2 June, he participated in an airshow watched by the president of the Republic. That same month he was posted to Armilla airfield, Granada, where he joined the 2^a Escuadrilla of the newly established Grupo de Caza N^o 12, which was part of Escuadra de Aviación N^o 2.

In early July 1936, the grupo was disbanded, and cabo Alonso Santamaría moved to Getafe airfield with his escuadrilla, which was led by capitan Méndez Iriarte.

When the civil war commenced he was a member of the 2^a Escuadrilla of the Grupo de Caza N^o 11, which flew Ni-H.52s from Getafe. Alonso Santamaría flew early combat missions with his fighter patrulla, which was led by sargento Andrés García La Calle while the third pilot in the patrulla was cabo Rafael Peña Dugo.

Cabo Alonso Santamaría of Grupo de Caza N^o 11 forced a Breguet XIX to land at Grajera airstrip on 25 July. At the time he was flying a Ni-H.52.

In August, sargento Andrés García La Calle’s fighter patrulla, made up of a Hawker Spanish Fury and two Nieuport Ni-H.52s flown by cabos Alonso Santamaría and Rafael Peña Dugo, moved to the Herrera del Duque and Don Benito airfields at Extremadura. The unit was commanded by teniente Ramón Puparelli Francia.
Later in the month the unit was sent to Talavera de la Reina airfield, in Toledo.

On 31 August, sargento Andrés García La Calle (Hawker Spanish Fury ‘4-1’) lead a fighter patrulla of two Ni-H.52 from capitán Juan Quintana y Ladrón de Guevara’s Escuadrilla Mixta, based at Talavera de la Reina. The two Ni-H.52s were flown by cabos Alonso Santamaría and wingman Rafael Peña Dugo.
Over Talavera de la Reina, southwest of Madrid, La Calle shot down a CR.32 while Alonso Santamaría and Peña Dugo shot down a second CR.32.
Both Alonso Santamaría and Rafael Peña Dugo were promoted to alférez after this success.

On one occasion (in September 1936?) the Ni-H.52 pair of sargentos Alonso Santamaría and Rafael Peña Dugo engaged a He 51 flown by teniente Julio Salvador Díaz-Benjumea. Although they believed they had downed the Heinkel fighter, Salvador managed to reach his airfield.

On 8 September 1936, he was promoted to alférez.

In late October/earl November, the Soviet command in Spain eventually permitted the best Spanish fighter pilots to join the two escuadrillas that had been established upon the I-15s’ arrival. Aviators such as Andrés García La Calle, Fernando Roig Villalta and Augusto Martín Campos soon began flying the biplanes, and although the latter pilot was quickly dismissed because the Soviet command did not trust him, further Spanish pilots joined the escuadrillas. They included José Cuartero, Emilio Galera, Jesús García Herguido, Alfonso Jiménez Bruguet, Manuel Aguirre López, Alonso Santamaría and Rafael Robledano Ruiz.

In November, the Soviet I-15 escuadrilla (1^a/Gr.26) led by kapitan Pavel Rychagov at Alcalá de Henares, in Madrid, included tenientes Andrés García La Calle (he was promoted to teniente during November), Alonso Santamaría, López Trinidad, Galera Macías, Cuartero Pozo, Guaza Marín, Roig Villalta, Jesús García Herguido, Alfonso Jiménez Bruguet, Manuel Aguirre López and Robledano Ruiz. The escuadrilla fought on the Madrid front.

He was promoted to teniente on 15 November 1936.

He was promoted to capitán on 1 February 1937.

By February 1937, capitán Ramón Puparelli Francia was well enough (he had been wounded in combat on 21 October 1936) to be given command of the first two Spanish I-15 escuadrillas. The short-lived grupo was named Grupo de Caza N^o 16 but both escuadrillas were to operate virtually independently.
Andrés García La Calle was put in command of the 1^a Escuadrilla. Initially it comprised three elements. The 1^a Patrulla consisted of La Calle, José Calderón, Ramón Castañeda di Campo and Ben Leider, the 2^a Patrulla comprised of Jim Allison, Frank Tinker, Harold Dahl and José ‘Chang’ Sellés and the 3^a Patrulla was made up of Luis Bercial, Esteban Ortiz, José Riverola Grúas and Gerardo Gil Sánchez (who joined the unit on 10 February).
Capitán Alonso Santamaría took command of the new second Spanish I-15 escuadrilla, the 2^a Escuadrilla, which was established at Los Alcázares and San Javier. From there they moved to El Soto airfield, again on the Madrid front. The new escuadrilla comprised tenientes Rafael Robledano Ruiz, Juan Comas Borrás (posted in late February), Antonio Blanch Latorre, Ricardo Rubio Gómez, Mariano Palacios Menéndez, Ángel Álvarez Pacheco, Justo García Esteban and Hipólito Barbeito Ramos, sargentos Manuel García Gascón, Alfonso Calvo Ortiz, Cándido Palomar Agraz and Rafael Magriña Vidal and Uruguayan teniente Luis Tuya.

Following enemy air raids on the power stations in Catalonia, the Jefatura de Operaciones of the Fuerzas Aereas ordered capitán Alonso Santamaría’s I-15-equipped 2^a Escuadrilla to the airfield at Lerida on 20 February. The eight-strong I-15 escuadrilla moved to Lérida the following day, with capitán Ramón Puparelli Francia (CO of the Grupo de Caza N^o 16, which comprised both Spanish I-15 escuadrillas) leading them. Its mission was a simple one - protect the Tremp and Camarasa power stations.
At the same time García La Calle’s 1^a Escuadrilla remained on the Madrid front.

In March, capitán Alonso Santamaría (CO of the Spanish 2^a Escuadrilla) moved to Alcalá de Henares airfield with two I-15 patrols, the third remaining on the Aragon front to participate in Guadalajara operations.

In April, the Spanish I-15 equipped 2^a Escuadrilla returned to the Aragon front, where capitán Alonso Santamaría and his escuadrilla were involved in the various aerial clashes that took place in this area during April. Sargento Alfonso Calvo Ortiz and Uruguayan teniente Luis Tuya were shot down, but the Republican pilots in turn claimed to have destroyed seven He 51s, although the enemy only admitted the loss of two aircraft.

Alonso Santamaría was finally withdrawn from frontline flying in the late spring of 1937, whereupon he test flew newly built I-15s emerging from the SAF-3 aircraft factory at Reus, in Tarragona.

Having survived many months of combat, he was killed during the summer of 1938 when his I-15 caught fire and crashed during a test flight from Sabadell, in Barcelona. The date of Alonso Santamaría's demise remains unknown.

He was a close friend of Andrés García La Calle, being romantically involved with one of his sisters.

At the time of his death, Alonso Santamaría was credited with 1 biplane victory.

Claims:

Kill no.	Date	Time	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1936
1	25/07/36		1	Breguet XIX (a)	Destroyed	Ni-H.52		Grajera airfield	Grupo de Caza No 11
	31/08/36		1/2	CR.32	Shared destroyed	Ni-H.52		Talavera de la Reina	Escuadrilla Mixta
	??/09/36		1/2	He 51 (b)	Shared destroyed	Ni-H.52			Escuadrilla Mixta

Biplane victories: 1 and 2 shared destroyed.
TOTAL: 1 and 2 shared destroyed.
(a) Forced to land.
(b) Possibly teniente Julio Salvador Díaz-Benjumea, who made it back to his airfield.

Sources:
Fiat CR.32 Aces of the Spanish Civil War - Alfredo Logoluso, 2010 Osprey Publishing, Oxford, ISBN 978-1-84603-983-6
Fighter Pilots Of The Spanish Republic (Vol. 1) - Rafael A. Permuy López, Historica 36/39 no. 1, ISBN 84-87314-89-9
Spanish Republican Aces – Rafael A Permuy López, 2012 Osprey Publishing, Oxford, ISBN 978-1-84908-668-4
Additional information kindly provided by Alfredo Logoluso and Ondrej Repka.