Whether you have a specific destination in mind or are seeking inspiration, knowing which airlines fly where is key.
I touched on this a bit in my previous post (link below) but this post will dive deeper.
How Do Airlines Decide on Routes?
First, let’s discuss what motivates airlines to operate flights between two cities. Many factors influence airline economics when deciding on specific routes, including:
- Origin and Destination (O&D): The number of people traveling between two points.
- Aircraft range and seat capacity: Whether the available aircraft can cover the distance and have the optimal amount of seats.
- Competition: The presence of other airlines on the same route.
- Airport slots: Availability of landing and takeoff slots at airports.
- Cargo demand: Airlines don’t just carry passengers, they also transport cargo
- Revenue and profitability: A combination of the above factors determines financial viability.
These factors directly influence how much you pay for your flight tickets.
Amongst these, Origin and Destination (O&D, O/D, or O-D for short) is a crucial metric. It indicates the number of passengers starting and ending their trips between two points. For instance, if a passenger books a ticket from San Francisco (SFO) to Singapore (SIN) with a layover in Hong Kong (HKG), the O&D pair is SFO-SIN, not SFO-HKG or HKG-SIN.
Sufficient O&D demand can make nonstop flights feasible, often leading airlines based in the origin or destination to operate these routes. For example, with enough passengers connecting between San Francisco and Singapore through Tokyo or Hong Kong, United Airlines launched a nonstop flight between San Francisco and Singapore in 2016.
How to Find Nonstop Flights?
Origin/Destination Airlines
The easiest way to find nonstop flights between two points is to check the airlines of the origin or destination. For example, if you’re flying between Sydney, Australia, and Los Angeles, United States, nonstop options include Qantas (Australia) or the major U.S. carriers: American Airlines, Delta Air Lines, and United Airlines (as of January 2025).
Nonstop flights are often the most expensive options because they cater to strong demand and charge a premium for convenience. Especially business travelers (whom airlines target for higher fares) value them for their time-saving nature and reduced hassle, as they eliminate the need for layovers and potential delays.
Key Takeaway: Nonstop flights between two points are typically operated by airlines of the origin and destination.
Fifth Freedom Flights
Fifth Freedom Flights refer to a specific international air service right allowing airlines to carry passengers or cargo between two foreign countries as part of a flight originating or ending in the airline’s home country. These flights are often more affordable than those operated by airlines of the origin or destination.
Examples of Fifth Freedom Flights (as of January 2025):
- Air China: Madrid (MAD) to São Paulo (GRU) as an extension of Beijing (PEK) to Madrid (MAD).
- British Airways: Singapore (SIN) to Sydney (SYD) as an extension of London Heathrow (LHR) to Singapore (SIN).
- Emirates: Athens (ATH) to Newark (EWR) as an extension of Dubai (DXB) to Athens (ATH).
- KLM: Kuala Lumpur (KUL) to Jakarta (CGK) as an extension of Amsterdam (AMS) to Kuala Lumpur (KUL).
- Singapore Airlines: Tokyo Narita (NRT) to Los Angeles (LAX) as an extension of Singapore (SIN) to Tokyo Narita (NRT).
These Fifth Freedom segments can be booked as standalone flights and are often cheaper than flights operated by the airlines of the origin or destination.
Key Takeaway: Nonstop flights between two points can also be operated by airlines that do not belong to the origin or destination.
European Common Aviation Area
The European Common Aviation Area (ECAA) created a Single Aviation Market across Europe. This agreement allows airlines from participating countries to operate freely within the area with minimal restrictions. It includes both European Union (EU) member states and some non-EU neighboring countries.
This framework has driven the rise of Low-Cost Carriers (LCCs) in Europe, offering more options for travelers, connecting underserved destinations, and catering to various price points.
Key Takeaway: Within the European Union (EU) Single Aviation Market, many airlines, including Low-Cost Carriers (LCCs), offer nonstop flights between destinations.
Final Thoughts
Understanding how airlines decide on routes and the different types of nonstop flights can help you make informed travel decisions. While I tend to opt for cheaper connecting itineraries mostly for status and points (after all, who doesn’t love to spend more time in the air and at the airports), whether you’re prioritizing convenience, cost, points, or availability, knowing the options available — from major carriers to Fifth Freedom flights and LCCs — can make your trip planning smoother and more efficient. In the next post, I plan to provide some insights for connecting itineraries. Until next time, have a safe flight!