Iag structure31 May 2017 10:30
These are the subsidiaries and Franchises;
Aer Lingus, Aer Lingus regional, British Airways, BA City Flyer, Open Skies, Comair, Sun-Air, IAG Cargo, Iberia, Air Nostrum, Iberia express, Level, Veuling.
Codeshares;
Cathay Pacific, Qatar, Air Baltic, Bangkok Airways, China Eastern, Flybe, Loganair, Meridiana fly, American Airlines, Japan Airlines, Qantas, Royal Jordanian, S7 Airlines, TAAG Angola Airlines, p of this,
On top of this there is also the collaborative membership of One World.
I might have missed some but it gives you some idea of their reach .