[5][6][7][8] Since its creation, IAG has expanded its portfolio of operations and brands by purchasing other airlines – BMI (2011), Vueling (2012) and Aer Lingus (2015).

[9][10][11] In April 2010, they signed a full merger agreement, with an intended completion date of late 2010, subject to securing the necessary regulatory approvals.

[25] On 8 November 2012, IAG made a cash tender offer to buy Vueling, a Spanish low-cost airline based in Barcelona.

[33] In March 2017, it was announced that a new low cost longhaul airline named LEVEL was to start operating from Barcelona in June 2017.

[34] On 29 December 2017, it was announced that IAG bought major parts of defunct Austrian leisure airline Niki including 15 Airbus A321 aircraft and traffic rights in Düsseldorf, Munich, Vienna, Zürich and Palma de Mallorca.

[41] On 20 January 2021, IAG announced that it had renegotiated its deal to acquire Air Europa (via Iberia) for €500 million as a result of the COVID-19 pandemic.

[42][43] In September 2021, IAG announced that British Airways would terminate its major short- and medium-haul base operations at Gatwick Airport with immediate effect resulting in the cancellation of more than 30 routes.

This came after labour negotiations regarding the handover of these operations, most of which were still suspended due to the COVID-19 pandemic, to a newly formed budget subsidiary within IAG failed.

[45] On February 23, 2023, IAG announced completion of a deal to purchase the remaining 80% of Air Europa for 400 million Euros.

[46] The European Commission, in January 2024, opened an in-depth investigation into proposed acquisition of Air Europa by IAG.

[53][54] It has secondary listings on the Madrid, Barcelona, Bilbao and Valencia stock exchanges,[55][56] and has been a constituent of the IBEX 35 index since 1 April 2011.

[59][60][61] IAG's operational headquarters, which controls the management of both its British and Spanish subsidiaries, are at the Waterside building in Harmondsworth, Greater London.

[83] British Airways, Iberia, Aer Lingus, Vueling and LEVEL operate under their separate brand names.

[93] Qatar Airways, the largest shareholder of IAG, switched to Avios as its frequent flyer currency in March 2022.