International Airlines Group is one of the world's largest airline groups. Transporting passengers and cargo generates revenue. It has multiple subsidiaries, and attempts to combine leading airlines in Ireland, United Kingdom, and Spain. It allows airlines to expand global presence and keep individual brands. Staff reports operating segments in a manner consistent with resource-allocation decisions, and are listed as four subsidiaries: British Airways, Iberia, Vueling, and Aer Lingus. Each segment is managed as individual operating companies. Revenue is split between the United Kingdom (roughly one third), Spain, the United States, and the rest of the world.