International operations began in earnest in 2018, when JetSMART launched flights from Chile to neighbouring countries, including Argentina and Peru. One of the most significant developments during this period was the establishment of JetSMART Argentina, a subsidiary that began operations in April 2019. Based primarily at El Palomar Airport near Buenos Aires, JetSMART Argentina aimed to replicate the Chilean low-cost model in a market historically dominated by legacy carriers and characterized by high fares. The Argentine subsidiary initially operated domestic routes such as Buenos Aires to Córdoba, Mendoza, and Neuquén, and later expanded to international services linking Argentina with Chile.

The period between 2019 and 2020 was marked by both expansion and disruption. JetSMART continued to take delivery of Airbus A320neo aircraft, steadily increasing its fleet size and replacing older A320ceo aircraft.

The airline also placed emphasis on ancillary revenue streams, including baggage fees, seat selection, and onboard sales, which are integral to the ultra–low-cost business model. However, the outbreak of the COVID-19 pandemic in early 2020 had a profound impact on JetSMART’s operations, as it did across the global aviation industry.

Governments in South America imposed strict travel restrictions, leading to a temporary suspension of many domestic and international routes.

During the height of the pandemic in 2020, JetSMART grounded a significant portion of its fleet and reduced capacity dramatically. Nevertheless, the airline maintained a focus on cost control and operational flexibility.

In 2021 and 2022, JetSMART resumed its growth trajectory, continuing to add new domestic and international routes. The airline expanded its presence in Peru by launching JetSMART Peru in 2022, establishing a third operating unit within the group. This move allowed JetSMART to tap into another large and growing aviation market. The Peruvian subsidiary began with domestic routes from Lima to cities such as Arequipa, Cusco, and Piura, and later introduced international flights connecting Peru with Chile and other neighbouring countries.

The airline continued to receive Airbus A320neo aircraft and began incorporating the larger Airbus A321neo into its fleet, which offers increased seating capacity and lower unit costs per seat. The A321neo enabled JetSMART to serve high-demand routes more efficiently and consider longer sectors within South America.