Every nonstop route is a bet. An airline commits an aircraft, crews and airport slots to a city pair for at least a season, and the route has to earn back those costs or it goes. That is why the list of direct flights from any airport keeps changing: new routes appear each spring, others vanish after a season or two, and a few run for decades.
This guide explains how airlines make that decision, in plain terms, and what it means when you are hoping for a nonstop from your own airport.
It starts with demand, and not just local demand
The first question is how many people want to fly between two places, and how much they will pay. Airlines estimate this from several sources:
- Existing traffic. Booking data shows how many passengers already travel between the two cities by connecting through a hub. If thousands a year fly from your city to a destination via a connection, some of them would switch to a nonstop.
- Fare levels. A route full of business travellers paying high fares can work with fewer passengers than a route of price-sensitive holidaymakers.
- Connecting traffic. A route from a hub does not need to be filled with local passengers. A flight from a big hub to a mid-sized city can carry people connecting from dozens of other flights. This is why hub airlines can serve destinations that look too small on their own.
- Cargo. On long-haul flights, freight in the hold can make the difference between a route that loses money and one that breaks even.
An airline will usually look at both directions. A holiday route can be strongly one-directional, with full flights out on Saturday and empty seats back, which drags down the average.
The aircraft has to match the route
Demand alone is not enough. The airline needs an aircraft with the range to fly the route, and with a size that matches how many people will buy tickets.
This is where new aircraft change the map. A route with demand for 150 passengers a day across the Atlantic could not support a 300 seat widebody. With the Airbus A321XLR, a single-aisle jet with transatlantic range, it can. Our guide to the A321XLR and long, thin routes covers the routes it has opened since 2024, such as Dublin to Nashville, and those already announced, such as United's Newark to Luxembourg from April 2027.
The opposite also happens. When an airline retires a type, routes that only worked with that aircraft can disappear if nothing in the fleet has the right size and range to replace it.
Slots: the right to use a busy airport
At many large airports, you cannot simply decide to fly there. Capacity is limited, so airlines need slots: permission to use the runway and terminal at a specific time.
Airports are classified under the IATA Worldwide Airport Slot Guidelines. The busiest are "Level 3", fully coordinated, where every flight needs an allocated slot. According to IATA, there are more than 200 Level 3 airports worldwide, and about half of all passengers depart from one.
In the EU, slot allocation follows Regulation 95/93. Its best known feature is the "use it or lose it" rule: an airline that uses a series of slots at least 80% of the time keeps priority for the same slots next season (so-called grandfather rights). The threshold was suspended and then lowered during the pandemic before returning to 80% from the summer 2023 season.
This has two effects on the routes you see:
- It can block new entrants. At a congested airport such as London Heathrow, an airline that wants to start a route usually has to buy, lease or swap slots from someone who already holds them, which makes the route more expensive to launch.
- It can keep marginal routes alive. An airline may keep flying a weak route rather than give up valuable slots it would lose by stopping.
Traffic rights: who is allowed to fly where
International routes also depend on agreements between governments. The basic permissions, such as the right to fly from your own country to another and carry passengers there, are described by the freedoms of the air and granted through bilateral or multilateral air services agreements. Inside the EU, a single aviation market means an EU airline can fly between any two EU airports. Outside it, a route may be impossible, or limited to a few airlines and frequencies, simply because the agreement between two countries does not allow more.
This is why airlines often announce new international routes as "subject to government approval": the schedule is ready, but the permission to fly it still has to be granted.
Airport incentives
Airports compete for airlines. Many offer discounts on airport charges for new routes, marketing support or other incentives, especially smaller and regional airports trying to win their first link to a particular city.
In the EU these incentives are regulated by state aid rules, because many airports are publicly owned. The European Commission's 2014 guidelines on state aid to airports and airlines allow start-up aid for new routes under conditions, in principle limited to airports with fewer than 3 million passengers a year, with exceptions for remote regions. The aid takes the form of a rebate of up to 50% on the airport charges for the route, for a maximum of three years, and the airline needs a business plan showing the route can pay its way without public money afterwards. In practice many airports offer transparent, non-discriminatory discounts that do not count as state aid at all.
Incentives explain why some routes appear suddenly at a regional airport. They also explain why some of those routes disappear after two or three years: when the discount ends, the economics change.
Seasonality
Few routes have the same demand all year. A leisure destination might fill flights every day in August and struggle to fill them in February. Airlines handle this in a few ways:
- Summer-only or winter-only routes. The route runs only in the months it pays.
- Fewer flights in the off-season. The route stays, but drops from daily to two or three a week.
- Moving aircraft between hemispheres or markets. Aircraft used on sun routes in summer can be redeployed to ski or city routes in winter.
You can see this in our own observed data. For Cagliari, we recorded actual departures over the 30 days to 5 October 2026. Some routes ran several times a day. Others, such as Cagliari to Bern and Cagliari to Salzburg, appeared only four times in that period, a pattern typical of a low-frequency or end-of-season service. Our guide to direct flights from Cagliari goes through the full list.
The launch decision in one table
| Factor | What helps a new nonstop | What works against it |
|---|---|---|
| Demand | Strong traffic already connecting via hubs, both directions | Weak or one-way demand |
| Fares | Business and premium travellers | Very price-sensitive market |
| Aircraft | A type with the right range and size | Only aircraft that are too big or too short-ranged |
| Slots | Spare capacity at both ends | Congested airports with no slots available |
| Traffic rights | Open-skies agreement or single market | Restrictive bilateral agreement |
| Airport | Incentives and marketing support | High airport charges |
| Competition | No existing nonstop | A strong rival already on the route |
Why routes disappear
A route can be cut for reasons that have nothing to do with how full the flights look to passengers.
It never reached its targets. New routes often take two or three seasons to build up. An airline will give a route time, but not indefinitely.
The aircraft is more valuable elsewhere. An airline has a fixed number of aircraft. If another route earns more per flight, the aircraft goes there, even if your route was making a small profit.
Costs changed. Fuel prices, airport charges and the end of an incentive deal can all turn a route from profitable to loss-making.
The airline changed strategy or failed. On 14 January 2021, Norwegian ended its long-haul operations, already grounded since March 2020, and with them a network of low-cost transatlantic routes from Europe to the US. Many of those city pairs had no nonstop afterwards.
Geopolitics and airspace. In March 2026, airspace closures linked to the Middle East conflict forced Qantas to add a fuel stop in Singapore to its Perth to London flight, which had been nonstop since 2018. The demand did not change; the route became physically longer. See Perth and our guide to the longest nonstop flights.
What this means if you want a nonstop from your airport
- Check every season. Routes are planned season by season. Winter and summer schedules can look very different.
- New routes are fragile. If you plan a trip a year ahead on a route that only started this year, have a backup plan in case it is cut.
- Fly the routes you want to keep. It sounds obvious, but airlines look at bookings, not wishes.
- Use the map as a guide to geography, not a timetable. Except for Cagliari, our route data comes mostly from an archive of around 2014. Many of those routes no longer fly, and many newer ones are missing. It is useful for seeing which cities an airport has historically been linked with, and our guide on how to find direct flights explains how to confirm what operates today.
Frequently asked questions
Why did my airport lose its direct flight?
The most common reasons are weak demand in part of the year, the aircraft earning more on another route, the end of an airport incentive deal, or a change in the airline's strategy. Sometimes the route returns the following season as a seasonal service.
How long does an airline give a new route?
There is no fixed rule. Many new routes are given at least a couple of seasons to build up, but airlines review performance continuously and can cut a route quickly if the aircraft is needed elsewhere.
What is an airport slot?
A slot is permission to use a coordinated airport's runway and terminal at a specific time on a specific day. At the busiest airports, every flight needs one, and airlines that use their slots at least 80% of the time keep priority for them in the next equivalent season under EU rules.
Can an airport pay an airline to start a route?
Airports commonly offer discounts and marketing support for new routes. In the EU, publicly funded support must follow state aid rules, which allow time-limited start-up aid under specific conditions, mainly at smaller airports.
Why are some routes summer only?
Because demand is seasonal. A leisure route that fills every flight in summer may lose money in winter, so the airline flies it only in the months it pays and uses the aircraft elsewhere the rest of the year.