Aviation in the US and Europe is dominated these days by large consolidated groups. The three largest airlines in the US have come together through a series of mergers and acquisitions, as have three of the four largest groups in Europe (Ryanair is the exception).
The current consolidation in Europe began with the merger of Air France and KLM in 2005. Since then, Air France-KLM has been joined by the Lufthansa Group and the International Airlines Group (IAG). This article explores each of these three groups.
Each of these has different reasons for its formation and how it has chosen to expand since. They also have differences in geographies. Lufthansa, for example, focuses on a group of neighboring countries, while IAG dominates the UK and Spanish markets. But at the core, all the airlines benefit from economies of scale, the ability to share orders and operations, and a vital boost in competing against growing low-cost carriers.