IAG, or the International Airlines Group, is arguably best known for its two largest flag carriers, British Airways, and Iberia. The group also contains LEVEL, Vueling, and Irish flag carrier Aer Lingus. Surprisingly, none of the flag carriers operated the most flights of the group this year, so which airline did?

2021 is likely to become a year that IAG would rather not remember. It was the year that the airline pulled out of its proposed Air Europa takeover deal. It was also a year where British Airways was up against constantly changing but consistently harsh flight restrictions. Despite this, the airline's cargo business continued to flourish, as Simple Flying recently reported.

Vueling was IAG's top airline in 2021

Surpassing both Iberia and British Airways, Vueling actually scheduled more flights around Europe this year according to schedule data from aviation data experts Cirium. The airline scheduled 111,321 flights in the 12 months from January to December, according to the data.

While the two major flag carriers didn't quite match this level of service, they did come close. British Airways had 108,148 flights scheduled this year, with its Spanish counterpart planning a total of 102,363. The schedule at Irish flag carrier Aer Lingus was much smaller, with just 24,428 flights planned for the year.

A year of new UK carriers

In 2021, two new UK subsidiaries were launched by the IAG group. Firstly, Aer Lingus branched out into the United Kingdom. Its new British subsidiary has begun long-haul transatlantic flights from secondary UK cities, complimenting the British Airways offering from London Heathrow and Gatwick airports.

Aer Lingus Manchester
Aer Lingus launched a UK subsidiary from Manchester. Photo: Aer Lingus

Meanwhile, British Airways has been working on a subsidiary of its own down at London Gatwick Airport. The airline has been losing money on short-haul operations long before the arrival of the COVID-19 pandemic. Suspending its operations from the airport gave the airline an opportunity to reassess its operations.

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Pending the arrival of a new AOC, the airline's Gatwick short-haul operations will move across to BA Euroflyer. While the same service should be present, prices should rival low-cost carriers thanks to lower operating costs. Simple Flying recently revealed that 97% of BA Euroflyer's routes will be shared with other carriers.

No Air Europa, yet…

Earlier this month, IAG revealed that it had pulled out of a deal to purchase Air Europa as it exists in its current form. While the airline group hasn't necessarily lost all interest in the Spanish carrier, it has pulled out of the deal that was on the table, leading to a financial penalty.

Air Europa, Boeing 787 Dreamliner, IAG
Photo: Getty Images

Backing out of the agreement cost the airline group €75 million ($85 million). The good news for IAG is that if it proceeds with the deal, the financial penalty paid to Air Europa will be credited to a future payment for the airline should a new deal go ahead.

Did you fly with IAG this year? How did you find your flight? Let us know in the comments!