The Central American nation of Guatemala had throughout most of the 19th century been ruled by a series of repressive dictatorships. In the 20th century, it has alternated between reform and reaction.
Entering a liberalization cycle, Guatemala had begun a series of major reforms in 1944. Under the presidency of Juan Jose Arevalo (1944-1951) and later Jacobo Arbenz Guzman (1951-1954), the government began to give more attention to the problems of middle- and lower-class Guatemalans, which had been largely neglected and even suppressed under previous administrations. A land reform process introduced in June of 1952 transferred large areas of unused agricultural land from large owners to landless peasants. However, this program had aroused the irritation of the United Fruit Company, which had owned huge banana plantations and which had powerful friends and allies in high places in the United States government. The Arbenz government began to be perceived by Washington as pro-Communist, and plans were set in motion against it.
In 1954, the government of Jacobo Arbenz Guzman was overthrown by a group of Guatemalan exiles armed and trained by the US Central Intelligence Agency (CIA) and led by Colonel Carlos Castillo Armas. After the overthrow of Arbenz, Armas became president, and for the next 30 years thereafter military officers dominated Guatemala. Many of the reforms were reversed, much of the expropriated land was returned to the large property owners, labor groups, political parties, and rural organizations were banned or severely restricted. Marxist parties were outlawed altogether.
Because of the CIA-sponsored coup against Arbenz, there was a close relationship between the Guatemalan military and Washington. In March of 1958, the government of Guatemala requested B-26 Invaders to replace the fleet of aged Beech AT-11s serving with the Fuerza Aerea Guatemalteca (Guatemalan Air Force). Six B-26s were asked for in the initial request.
However, in February 1959 discussions with the US State Department over the B-26 order were suspended because of friction between Mexico and Guatemala over fishing rights, the US fearing that the sale of the planes to Guatemala might trigger an arms race in Central America.
That would ordinarily have been the end of the matter, but the Central Intelligence Agency (CIA) was at that time hatching a plan for a Cuban exile group to overthrow the new regime of Fidel Castro which had tilted sharply toward the Soviet Union. Since Guatemala was to play a key role in the invasion plan, all objections to the sale of B-26s to Guatemala were now suddenly brushed aside. In 1960, eight Invaders were withdrawn from storage, overhauled at Davis Monthan AFB and delivered to Guatemala.
Although the B-26s were marked in FAG insignia and were given FAG serials, at least six of these planes were actually sent to the remote airfield at Retalhuleu where they served as training aircraft for the Cuban exile elements of Brigada 2506, the CIA cover unit for the invasion and retaking of Cuba.
The Cubans trained on these aircraft until April of 1961, when the brigade's aircrews left for Puerto Cabezas in Nicaragua to stage the attack. The B-26 aircraft at Retalhuleu remained behind and were then turned over to the FAG.
Like most long-serving B-26s, the FAG Invaders suffered from wing spar fatigue problems, and the surviving FAG aircraft went through the Project Wing Spar program in the Canal Zone in 1964-65. By December 1966 five were still operational. However, by December 1967, the FAG B-26s were only rarely being flown due to personnel problems and lack of funds. By September 1968, although still listed as being on strength, the FAG B-26s were actually completely inactive and had not been flown for a year and were more or less standing derelict. They had become redundant for all practical purposes by the end of 1968. They were finally replaced by Cessna T-37Cs. I don't know if any still survive today.