Southwest and China Airlines Launch Strategic Interline Partnership 2026

Southwest and China Airlines Forge Strategic Interline Partnership: A New Era of Connectivity

In a notable move that signals a shift in strategy, Southwest Airlines and China Airlines have announced a new interline partnership set to launch in early 2026. This collaboration marks a pivotal moment for Southwest, traditionally a domestic, low-cost carrier, as it takes a step toward becoming more globally connected. The agreement will allow passengers to book seamless itineraries through major U.S. West Coast airports, including Los Angeles (LAX), San Francisco (SFO), Ontario (ONT), and Seattle (SEA).

For China Airlines, the flag carrier of Taiwan, the partnership opens up greater access to Southwest’s extensive U.S. domestic network, enhancing connectivity for its international passengers. The move reflects a broader industry trend of airlines forming low-commitment alliances to offer travelers more comprehensive route options without the complexity of full mergers or alliances.

While not a codeshare or loyalty program integration, the interline agreement is a pragmatic step for both carriers. It allows for coordinated baggage handling and single-ticket itineraries, simplifying the travel experience for passengers connecting between Asia and the United States.

Understanding the Interline Agreement and Its Implications

What Is an Interline Agreement?

An interline agreement is a cooperative arrangement between two or more airlines that allows them to issue tickets on each other’s flights. This enables passengers to book a single itinerary across multiple carriers, check in once, and have their baggage transferred automatically to their final destination. It’s a streamlined approach to travel that benefits both airlines and passengers.

In the case of Southwest and China Airlines, a traveler flying from Taipei (TPE) to Los Angeles (LAX) on China Airlines could continue on to Las Vegas (LAS) or Denver (DEN) on Southwest, all under a single booking. While passengers will still need to check in separately for each segment, the convenience of one itinerary and one baggage process is a clear improvement.

This partnership does not include codesharing—where flights are marketed under multiple airline designators—nor does it integrate frequent flyer programs. However, it lays the groundwork for future collaboration and reflects a flexible, low-risk approach to expanding international connectivity.

“This interline partnership is a strategic win for both carriers. Southwest gains a bridge to Asia without the risks of direct long-haul operations, and China Airlines enhances its U.S. domestic feed.” , Kevin Derby, Aviation Analyst

Strategic Benefits for Southwest and China Airlines

For Southwest Airlines, this interline deal is its second global partnership after Icelandair and its first trans-Pacific collaboration. It represents a significant shift from its historical focus on domestic operations. By tapping into China Airlines’ long-haul international network, Southwest can offer its customers broader travel options without overhauling its fleet or operational model.

China Airlines, on the other hand, gains a valuable partner in the U.S. domestic market. With limited presence from Delta Air Lines, China Airlines’ SkyTeam ally, in certain West Coast gateways like Ontario (ONT), Southwest’s strong footprint offers a strategic advantage. This allows China Airlines to provide better onward connectivity for its passengers arriving in the U.S.

According to the International Air Transport Association (IATA), interline agreements can boost passenger volumes by up to 10–15% on connecting routes. While the financial impact of this deal may be modest initially, the long-term benefits in terms of network reach and customer satisfaction are noteworthy.

Industry Trends and Market Context

The airline industry is witnessing a resurgence of collaborative models as carriers recover from the disruptions caused by the COVID-19 pandemic. Partnerships like this one offer a practical way to rebuild route networks and enhance passenger experience without the legal and operational complexities of mergers or full alliances.

Asia-Pacific remains the fastest-growing aviation market, with increasing demand for travel between Asia and North America. This interline agreement aligns with both airlines’ strategic goals—Southwest’s gradual international expansion and China Airlines’ efforts to strengthen its North American footprint.

Globally, the airline industry generated approximately $838 billion in revenue in 2023, with North America and Asia-Pacific leading in market share. As competition intensifies and passengers seek more seamless travel experiences, such partnerships are becoming essential tools for network optimization.

“Interline agreements remain a vital tool for airlines to offer passengers more seamless journeys. For Southwest, which traditionally avoided alliances, this partnership signals flexibility and a recognition of evolving passenger expectations.” , Jane Smith, Aviation Consultant

Challenges and Future Opportunities

Operational and Integration Considerations

While the interline agreement is a step forward, it also presents operational challenges. Integrating ticketing systems, training staff, and coordinating schedules require careful planning. The timeline—bookings available in late 2025 and flights beginning in early 2026—provides a buffer for these preparations.

Passenger education will also be crucial. Travelers unfamiliar with interline arrangements may expect a fully integrated experience, including shared check-in counters or loyalty benefits. Clear communication will be key to managing expectations and ensuring a smooth rollout.

Despite these hurdles, the partnership provides a valuable test case for Southwest. It enables the airline to assess the viability of more extensive international collaborations without significant capital investment or operational risk.

Potential for Expanded Collaboration

Looking ahead, this interline agreement could pave the way for deeper integration. If passenger demand and operational performance meet expectations, Southwest and China Airlines might explore codesharing, loyalty program reciprocity, or even joint marketing initiatives.

Such developments would align with industry trends where airlines seek to offer a “virtual alliance” experience—providing many of the benefits of full alliances without the formal commitments. This flexibility is particularly appealing in a post-pandemic world where agility and responsiveness are paramount.

For now, the interline agreement serves as a low-risk, high-reward strategy for both carriers. It enhances connectivity, improves customer experience, and positions both airlines for future growth in a competitive global market.

Conclusion

The interline partnership between Southwest Airlines and China Airlines marks a strategic evolution for both carriers. For Southwest, it represents a cautious yet meaningful entry into the realm of international connectivity. For China Airlines, it enhances access to the U.S. domestic market through a reliable and extensive partner.

As the airline industry continues to adapt to new realities and customer expectations, such partnerships offer a flexible path forward. They allow airlines to expand their networks, improve passenger experience, and remain competitive without the complexities of deeper alliances. This agreement is a sign of things to come—a more interconnected and collaborative future for global aviation.

FAQ

What is the difference between an interline agreement and a codeshare?
An interline agreement allows airlines to issue tickets on each other’s flights and coordinate baggage handling, but passengers must check in separately. Codesharing involves marketing flights under both airlines’ codes and often includes loyalty program integration.

When will the interline partnership between Southwest and China Airlines begin?
Bookings are expected to open in late 2025, with flights commencing in early 2026.

Will frequent flyer programs be integrated under this partnership?
No, the agreement does not include loyalty program integration. Passengers will not be able to earn or redeem miles across the two carriers.

Sources: Aviation A2Z, Southwest Airlines, China Airlines, IATA, CAPA, Centre for Aviation, Wikipedia, LapZone, IATA, IATA, Simple Flying