How an Airline Plans Its Network

Airline network planning is the work of deciding which pairs of cities an airline connects, how often, with which aircraft and at what times of day. A flight between two cities exists only when several things are true at once: enough people want to make that trip, the airline has an aircraft that can fly it and earn its keep, the countries involved allow it, the airports have room for it, and it fits the rest of the network. Take away any one of those and the route does not get flown, however obvious it looks on a map.

The questions a network planner answers

In MIT's airline management course, Peter Belobaba sets it out as fleet planning, then route planning, then schedule development, which itself breaks into four questions: how often (frequency planning), at what times (timetable development), with what type of aircraft (fleet assignment), and how the aircraft move through the network so each one ends up where it is needed next (aircraft rotation planning) (MIT OpenCourseWare, "Airline Schedule Development," captured 2026-09-27).

The same lecture puts the timing plainly: the process "begins a year or more in advance and continues until actual departure time." Frequency plans come first, timetables and aircraft rotations are defined two to six months ahead, and revisions keep coming until the flight leaves. Pricing, crew scheduling and day-of operations control all sit downstream of the network.

Condition 1: enough people want to travel between the two cities

Planners start from demand in an origin-destination market, meaning everyone who wants to get from city A to city B, whichever airline or routing they end up using. Belobaba's lecture lists what drives the number of flights on a route: an estimate of total demand between origin and destination, the share of that demand the airline expects to win (which depends on its frequency relative to competitors), and "potential for additional traffic from connecting flights" (MIT OpenCourseWare, captured 2026-09-27).

That last point matters. A flight from a hub to a mid-sized city also carries people who started somewhere else and are changing planes, so a city pair that looks too thin on its own can work once the connecting traffic is counted.

Frequency is part of the demand picture too. The same lecture notes that more departures cut the wait between flights, that peak morning and late-afternoon times attract more travellers in many markets, and that frequency "is much more important in short-haul markets than for long-haul routes," where the flight time itself dominates. A short business route may need several flights a day to compete; a long-haul route may work with one.

Condition 2: an aircraft that can fly it and pay for it

Demand on paper is not enough if the fleet cannot serve the route well. The aircraft has to reach the destination with a commercial load, and its size has to match the demand at the frequency the airline wants.

New aircraft change the answer. Airbus describes its A321XLR, a single-aisle jet, as having a range of up to 4,700 nautical miles (about 8,700 km) and flights of up to 11 hours, with 180 to 220 seats in a typical two-class layout, and names pairs such as Delhi to London among the city pairs it can connect (Airbus, A321XLR product page, captured 2026-09-27). A smaller aircraft with that range lets an airline test a long route whose demand would not fill a large twin-aisle jet.

Fleet assignment then decides which type flies which leg. The MIT slides frame it as maximising contribution, revenue minus costs, across the whole schedule rather than route by route.

Condition 3: permission to fly it

Inside the United States, the 1978 Airline Deregulation Act removed the regulation of fares, routes and schedules in the domestic market (European Parliamentary Research Service, "EU external aviation policy," October 2019, captured 2026-09-27). International routes are different: they need permission from governments. Article 6 of the 1944 Chicago Convention says no scheduled international air service may be operated over or into a contracting state's territory "except with the special permission or other authorization of that State" (same briefing).

In practice that permission comes through bilateral air services agreements between countries. The same briefing explains that these agreements have traditionally covered the freedoms of the air being granted, the airlines designated to fly, and capacity: "the number and frequency of flights, type of aircraft on the agreed routes." The third and fourth freedoms, which let an airline carry passengers from its home country to another and back, are granted together. The fifth freedom lets a carrier pick up and set down passengers between two foreign countries, provided the flight begins or ends in its home country.

So a route can have the demand and the aircraft and still wait for a treaty. If an agreement caps the number of flights and that cap is already in use, adding a service means changing the agreement first.

Condition 4: a time to land

At busy airports, permission to fly the route is not the same as permission to land at a particular hour. IATA describes airport slot coordination as the process that "allocates scarce airport capacity to airlines in advance of each scheduling season," and counts more than 200 fully coordinated (Level 3) airports and more than 160 Level 2 airports worldwide, with 50% of all passengers departing from a Level 3 airport (IATA, Airport Slots, captured 2026-09-27). The rules for how slots are declared and allocated are set out in the Worldwide Airport Slot Guidelines, published jointly by IATA, Airports Council International and the Worldwide Airport Coordinators Group (IATA, Worldwide Airport Slot Guidelines, captured 2026-09-27).

For a planner this is a timing problem: if the only slot on offer is at an hour nobody wants to fly, the route may not work even when every other condition is met.

Condition 5: it fits the hub

For an airline that runs a hub, a new route has to serve the hub as much as the two cities. Belobaba's slides call this "load consolidation": a network lets one flight carry passengers bound for many different final destinations, which in turn lets the airline run more frequency or bigger aircraft. The lecture calls it "a fundamental reason for economic success of airline hubs."

The timing of the route has to line up with the connecting flights at the hub, too. A flight that lands just after the onward departures have left loses much of its connecting traffic, so planners fit new routes into the hub's existing pattern of arrivals and departures.

Three city pairs, read through the checklist

A Singapore to London route covers 10,887 km great-circle (Great Circle Mapper, captured 2026-09-27). On this checklist it is an aircraft-and-permission question first: the distance calls for a long-range twin-aisle aircraft, and as a flight between two countries it sits under the agreements between them. And as with any long route between two large cities, the demand estimate counts passengers connecting at either end as well as those starting and finishing there.

A Newark to Santo Domingo route is 2,505 km great-circle (Great Circle Mapper, captured 2026-09-27), well within single-aisle range. Here the aircraft is the easy part. The planning questions shift to demand in the origin-destination market, the frequency needed to compete, and whether the timetable fits the rest of the operating airline's schedule.

Dubai International shows what the hub condition looks like at scale. Dubai Airports reports that in 2025 the airport handled 95.2 million passengers and ended the year connected to 291 destinations in 110 countries, served by 108 international airlines, with London its top city market at 3.9 million passengers (Dubai Airports, 2025 traffic release, published 2026-02-11, captured 2026-09-27). A network of that width means a new route from Dubai can draw on passengers connecting from many other cities, which is the load consolidation effect from the section above.

How TrackMyWings helps

TrackMyWings™ is a live flight-tracking platform in development. A private beta has been running on Android since 2026-08-24, on the Play internal testing track, and public launch has no fixed date. A live map and gate and status alerts are among the features planned for launch, so that once a network planner's decisions become a flight you or someone you love is on, you will be able to follow it. Meanwhile, the directory pages for the Singapore to London route, the Newark to Santo Domingo route and Dubai International are a starting point for the city pairs above.

Questions people ask

How far ahead do airlines plan new routes? The planning process begins a year or more before the first flight, according to MIT's airline management course material. Frequency is set first, while timetables and aircraft rotations are typically fixed two to six months ahead, with revisions up to departure.

Why doesn't an airline fly a route that seems obviously popular? Demand is one condition of five. The airline may lack a suitable aircraft, the countries may not have agreed the rights, the airport may have no slot at a usable time, or the timing may not fit the hub.

Do airlines need government permission to start an international route? Yes. Under Article 6 of the Chicago Convention, a scheduled international service needs the permission of the state it flies over or into, usually granted through a bilateral air services agreement.

Why do some routes get several flights a day and others one? Frequency matters most on short routes, where waiting for the next flight is a large share of total trip time. On long-haul routes the flight itself dominates, so one daily service can compete.

Sources

• MIT OpenCourseWare, Peter Belobaba, "Airline Schedule Development" (16.75J Airline Management, 22 February 2006), https://ocw.mit.edu/courses/16-75j-airline-management-spring-2006/a28aa07c64a983ce2cd475b9f7e32f16_lect5.pdf, captured 2026-09-27
• European Parliamentary Research Service, "EU external aviation policy" (PE 642.221, October 2019), https://www.europarl.europa.eu/RegData/etudes/BRIE/2019/642221/EPRS_BRI(2019)642221_EN.pdf, captured 2026-09-27
• IATA, Airport Slots, https://www.iata.org/en/programs/ops-infra/slots/, captured 2026-09-27
• IATA, Worldwide Airport Slot Guidelines, https://www.iata.org/en/programs/ops-infra/slots/slot-guidelines/, captured 2026-09-27
• Airbus, A321XLR, https://www.airbus.com/en/products-services/commercial-aircraft/passenger-aircraft/a320-family/a321xlr, captured 2026-09-27
• Dubai Airports, 2025 traffic release (published 2026-02-11), https://media.dubaiairports.ae/dxb-sets-global-benchmark-as-record-traffic-become-the-norm/, captured 2026-09-27
• Great Circle Mapper, SIN-LHR and EWR-SDQ in km, http://www.gcmap.com/dist?P=SIN-LHR,EWR-SDQ&DU=km, captured 2026-09-27