On January 11, 1925, he was commissioned to become a flight instructor and on May 24, 1926, he travelled to the United States to undergo a special aeronautics course in the military school located in Brooks Field, Texas.

On December 7 of 1923, ex-President Adolfo de la Huerta launched a military coup later called the delahuertista rebellion against the government of President Alvaro Obregón.

Mexico quickly reequipped and reorganized the military aviation and, with the help of the United States, it received new combat airplanes consisting of several de Havilland DH-4B with Liberty motor, armed with Lewis and Vickers machine guns and able to carry bombs.

Then, Farell attacked enemy convoys in Iguala, Pachuca and intermediate locations in company of his friend Squadron Commander Roberto Fierro VIllalobos.

He later moved on to attack rebels operating in the southern states of Tabasco, Oaxaca and Chiapas, where their engine failed and crashed in the dense jungle; fortunately, they were unharmed.

In January 1924, Farell began his duties in the north-western front against the Generals Enrique Estrada and Manuel Macario Diéguez, who controlled most of Chihuahua, Jalisco, Guanajuato, Michoacán and Durango states.

Since the Lerma River divided to the troops of both sides, the artillery and the Air Force were indispensable during the early hours of combat: At 07:00AM Farell's squadron flew the first of two missions, bombing and strafing the enemy until ran out of ammunition.

Some fellow fliers were men like Alfonso Cruz Rivera, Roberto Fierro Villalobos, Pablo Sidar, Emilio Carranza, Eliseo Martín del Campo, Guillermo Monroy, Manuel Solís, Julián Nava Salinas, Francisco Espejel, Alberto Vieytez, Ricardo Díaz Gonzáles and Luís Rojas, among others.

For his valuable participation against the Adolfo de la Huerta coup, General Lázaro Cardenas, who was present at his aerial attacks, promoted Luis Farell to the degree of Captain because of “special merits during battle”.

Between 1926 and 1927 and while under the command of brigadier General Antonio Rios Zertuche, Major Roberto Fierro and Colonel Samuel Carlos Rojas, Luis Farell completed several missions against the Yaqui Indian rebels in the state of Sonora.

Several years after this campaign, Farell expressed to his family the moral difficulties of having battled against these indigenous people, whom demanded by the force that previous territorial treaties were implemented.

[7][8] In this context, the government of Mexico convinced the US to promote the peace south of its border and quickly make available twelve new OU-2M Corsair with the 400 hp Wasp engine, nine Douglas O-2M, four Stearman C3B and six Waco 10.

Only two weeks after making the request, the USA government agreed and Farell and other pilots travelled to Brownsville, Texas and New York City to pick up the new aircraft.

It is recorded that Luis Farell flew a total of 52 combat hours over the states of Nuevo León, Coahuila, Durango and Chihuahua, when he was wounded by a bullet.

On March 19, 1929, while in company of Lieutenant Colonel Pablo Sidar, Roberto Fierro, Ismael Aduna, Luis Boyer, Arturo Jiménez Nieto, Antonio Cárdenas Rodríguez, Carlos Rovirosa, Rodolfo Torres Rico and Gustavo León, Luis Farell attacked enemy positions in Benavides, Coahuila and the following five days, from 20 - 25 of March, he bombed telegraph lines, bridges, locomotives and the railroad out of the city of Jiménez, Chihuahua in order to cut the enemy's escape and communications.

Finally, on March 25, 1929, Farell's squadron attacked Escobar's operation centers in the cities of Escalon and Jiménez, and while making a low altitude strafing run with a WACO aircraft, he was shot in both legs.

On January 1, 1934, the newly elected President Lázaro Cárdenas again appointed him as 'Jefe del Estado Mayor Presidencial' and in November 1934, was promoted to Lieutenant Colonel of the Air Force.

Luis Farell and an old friend, Coronel Alfredo Lezama Álvarez, organized a mixed fleet of 17 aircraft and flew several missions, engaging the enemy assertively when spotted.

[13] During this confrontation, Farell flew the new V-99M Corsairs which had the capacity to carry bombs and were equipped with the 550 hp Pratt & Whitney R-1340-T1H-1 Wasp engine and two Colt 0.30 machine guns, one fixed at the front and one for the artilleryman.