In the 1940's, when World War II began, the airline continued to grow with the help of Pan Am, which owned 25% of the new Mexican airline. Aeroméxico saw few changes for the next two decades. However, during the 1950s, renovation began, and the airline took over various small competitor companies across the country, including Aerovías Guest that held the routes to Madrid and Paris. Aeroméxico added aircraft including the Douglas DC-3 and the Douglas DC-4.During the late 1950s, the Douglas DC-4s were replaced by pressurised Douglas DC-6s and two Bristol Britannias (the first turboprop passenger aircraft in the fleet) and in 1958, services were inaugurated to Idlewild Airport (now JFK) using the Britannias. The airline was nationalised in 1959. 

In the early 1960s, "Aeronaves" began replacing its piston-engined aircraft with new jets. The first jet-engined aircraft were a pair of Douglas DC-8s. The 1970s brought dramatic changes for Aeroméxico. In 1970, under a government plan, Mexican domestic airlines were nationalized into an integrated air transport system under the control of Aeronaves de México. A new color scheme (orange and black) was introduced and the airline changed its name from "Aeronaves de México" to its current, shortened version of Aeroméxico in February 1972. 

Aeroméxico, as one of the launch customers of the McDonnell Douglas DC-10-30 program, it received the first of its aircraft in 1974. That same year the airline also took delivery of its first seven McDonnell Douglas DC-9-32s. The early 1980s were marked by expansion. A new colour scheme was introduced (orange paint and silver), two DC-10-15s and a DC-10-30 were added in 1981. In 1984 Aeroméxico, was one of the launch customers of the McDonnell Douglas MD-82.  

The early 1990s were turbulent times, with the rise in fuel costs due to the Gulf War, and a domestic fare war caused by start up airlines like TAESA, Servicios Aéreos Rutas Oriente, Aviacsa, among others, as well as constant labor problems. In April 1991 the first two 767-200ERs were introduced to the fleet starting to replace DC-10s in services to Europe, New York and Tijuana. This was all a part of a renovation and expansion program to introduce 24 direct flights to Madrid and Paris from Mexico City with Boeing 767s as well as services to Frankfurt via Paris and Rome via Madrid. 

In 1993 Aeroméxico Group took over Mexicana, the second largest airline in the Mexican market under the same management. In December 1994, the first of several devaluations in the next 18 months started, giving way to an economic crisis in Mexico. As a consequence, Aeroméxico had to cut capacity and flights to Frankfurt and Rome were cancelled, four McDonnell Douglas MD-80s and four Boeing 767s were returned to their lessors.

Between 2000 and 2005, Aeroméxico had an average fleet of 60 aircraft in mainline operation, plus 20 in Aerolitoral. In 2003, the airline acquired its first Boeing 737-700 instead of the Boeing 717 as a replacement for its aging DC-9 aircraft. On 29 March 2006 Aeroméxico, announced the inauguration of direct flights between Japan and Mexico City via Tijuana. This was after the purchase of two Boeing 777-200ERs, making Aeroméxico the third airline in Latin America to fly regularly to Asia.

On 29 June 2006, the International Lease Finance Corporation (ILFC) and Aeroméxico announced that the airline would operate three Boeing 787 Dreamliners. Aeroméxico's deliveries were scheduled to begin in early 2012.