Delta is being challenged by United as the world's most profitable airline.

The U.S. airline that has outperformed all others this year also aims to become the most profitable carrier.

Since January 1, United shares have experienced an increase of over 80%, surpassing the profit gains of the country's leading airline, Delta, by more than double.

For almost a century, United Airlines has been the world's largest airline in terms of capacity. In an effort to increase profits, the Chicago-based carrier has been investing heavily in more spacious seats and expanding its network to attract high-spending travelers, with routes extending beyond typical vacation destinations to places like Greenland and Mongolia.

"Patrick Quayle, United's senior vice president of global network planning and alliances, stated that by providing more seats at various price points, the airline has been able to compete with low-cost carriers in a cost-effective manner for basic economy travelers. Additionally, this strategy allows United to compete with foreign flag carriers by offering a superior product in the front of the cabin."

United has the most international routes of any U.S. airline.

"Andrew Nocella, chief commercial officer of United Airlines, stated that they have not yet achieved their goal domestically and are currently ranked third or fourth, depending on the measurement. However, he believes they have a lot of room for growth and improvement in the future."

The two leading U.S. airlines are engaged in a competition to attract customers.

According to Henry Harteveldt, president of Atmosphere Research Group, United Airlines is striving to become a more premium airline, similar to Delta's long-standing reputation.

Hundreds of planes are being outfitted with Bluetooth connections, new screens, and free Wi-Fi starting in 2025, provided by Space X's Starlink.

Delta has updated its lounges, with separate areas for long-haul business class travelers and free Wi-Fi, as well as enhanced first class seats with increased privacy.

Watch the video to learn more.