World's biggest airline 2021: US airline reclaims title as world’s largest carrier

American Airlines has taken the pandemic as an opportunity to reemerge as the world's largest airline, a title it has traded back and forth with competitors during the last few years as Delta and United expanded their networks.

But American Airlines has pulled ahead of rival Delta and is reestablishing routes and reconnecting with passengers to coincide with the uptick in summer travel. Based on flights scheduled, seat counts and how many passenger miles it has planned, American has been the biggest carrier in the world since April, according to airline schedule tracker Diio by Cirium.

In fact, American's June schedule is about 21 per cent bigger than Delta, its next largest rival.

"American has been aggressive," said John Grant, the UK-based chief analyst for aviation data firm OAG. "You are very lucky in the United States to have a large domestic market."

A handful of global rivals have traded the title of the world's largest airline during the COVID-19 pandemic as the ongoing outbreak upended the aviation world. At different times over the last 15 months, Qatar Airways, China Southern and even Dallas-based Southwest Airlines have scheduled the most flights and passenger kilometres.

American Airlines has reason to be on top. It has more planes and more employees than any airline in the world. It would only seem natural to put those employees and planes to work. It's also trying to dig out of the financial hole created by the pandemic. In May, for the first time in more than a year, American Airlines actually "generated cash" after figuring in operating expenses.

Airlines are still cautious as they emerge from the global COVID-19 pandemic, with business travel still suffering greatly and international borders still largely restricted for vacationers.

American is running about 85 per cent of the number of flights it ran in 2019 this summer and 80 per cent as many passenger seat miles, a key figure in the airline industry that tracks the total number of miles and passengers flown in each plane. But by comparison, Atlanta-based Delta's operation is still down about 32 per cent from 2019, and United is running an even more conservative schedule with a 40 per cent schedule reduction compared with 2019.

American has been joined in its bullish strategy by Dallas-based Southwest, which is running almost as many flights this year as it did in 2019, a year when it was extremely constrained by the grounding of the Boeing 737 Max. But Southwest has natural advantages that other airlines don't. Almost all of its flights are in the United States or to short-haul international destinations in the Caribbean and Mexico, areas that have largely remained open to travellers and have been busy tourist spots during the pandemic.