1. Star Alliance: Includes airlines such as Lufthansa, United, Air Canada, Singapore Airlines, ANA, Turkish Airlines, and Thai Airways.
Benefit for Complex Itineraries: Offers the largest global network, making it ideal for multi-city and round-the-world itineraries. Provides seamless interline ticketing, through-checked baggage, and lounge access reciprocity for eligible premium passengers.
2. Oneworld: Includes airlines such as British Airways, American Airlines, Cathay Pacific, Japan Airlines, Qatar Airways, and Iberia.
Benefit for Complex Itineraries: Strong connectivity across the North America–Europe–Asia corridor, with high-quality premium cabin experiences and consistent frequent flyer mileage earning (e.g., Avios ecosystem).
3. SkyTeam: Includes airlines such as Air France, KLM, Delta, Korean Air, China Southern, Aeromexico, and Vietnam Airlines.
Benefit for Complex Itineraries: Provides strong coverage across the Atlantic routes, solid access to Asia via Korean Air and China Southern, and useful connections into Latin America through Aeromexico.
Codeshare vs. Interline vs. Online Connection
| Connection Type |
What It Means |
Agent Implication |
| Online Connection |
Both flights operated by the same airline (same IATA code) |
Highest protection; airline is fully responsible for missed connections; baggage checks through automatically |
| Codeshare Connection |
One airline sells a seat on another airline's plane under its own flight number |
The marketing carrier's flight number appears on the ticket; operating carrier is responsible for operations; confirm which airline holds the actual seat |
| Interline Connection |
Two separate airlines that have an agreement allowing through-ticketing and baggage transfer |
Less protection than codeshare; if one carrier causes a delay, the interline partner is not obligated to rebook on its own metal |
| No Agreement (Virtual Interline) |
No formal commercial agreement; connection is self-arranged |
No through-baggage; no protection; treated as separate tickets; client must collect and recheck bags; agents should avoid unless the client accepts the risk explicitly |
Baggage Through-Check Rules
Through-checking of baggage is one of the most important practical issues in complex itineraries. Clients assume their bags will always follow them — they do not:
1. Baggage checks through automatically on a single PNR (Passenger Name Record) where all flights are ticketed together and the airlines have an interline agreement.
2. On split tickets, the client must collect and recheck bags at every connection — even if both flights are operated by the same airline. This is a critical briefing point.
3. Some budget carriers (particularly in Europe and Southeast Asia) do not participate in interline agreements at all. Any connection through a low-cost carrier on a separate ticket requires manual re-check.
4. Where baggage does not check through, ensure the layover time allows for baggage collection and re-check, including any re-clearance through immigration or customs.