Airport capacity: declared capacity, movements per hour and runway systems

At the fence it sometimes seems as if one aircraft after another keeps coming in without end – and at another airport you wait twenty minutes for the next landing. There’s more behind that than just demand. Every larger airport has a defined capacity in movements per hour, and it results mainly from the runway system. This guide explains what declared capacity is, why two runways aren’t the same as two runways and what the numbers mean for your planning at the spot.

Airport capacity: the short answer

An airport’s capacity describes how many takeoffs and landings it can safely handle in a given period – in practice usually per hour. At heavily demanded airports, a binding value is derived from it, the coordination parameter. It sets how many slots per hour may be allocated. Anything beyond that value simply gets no place in the flight schedule.

The difference between three quantities matters:

• Technical capacity: What runways, airspace and air traffic control can theoretically deliver under good conditions.
• Declared capacity: The fixed upper limit for slot allocation – usually somewhat below the technical maximum, so that delays and weather don’t immediately lead to chaos.
• Actual movements: What really happens in a specific hour. At off-peak times that’s far below the declared capacity, at peaks close to it.

Who sets the declared capacity

In Germany, the Flughafenkoordinator der Bundesrepublik Deutschland (fluko, the airport coordinator of the Federal Republic of Germany) handles slot allocation at the heavily utilized airports. These are classified as Level 3, meaning fully coordinated: anyone who wants to take off or land there needs a slot in advance. Currently this applies to Berlin Brandenburg, Düsseldorf, Frankfurt, Hamburg, Hannover, Cologne/Bonn, Munich and Stuttgart. There are also Level 2 airports, where flight schedules are only harmonized but not strictly coordinated.

For each flight schedule period, the coordinator publishes the so-called capacity parameters. These include not only runways but also approach and departure procedures, separation rules, taxiways, apron positions, terminals and checkpoints. On top of that come restrictions from environmental and neighborhood law, such as night flight rules. How slots are allocated, swapped and lost in detail is explained in the guide Slots at airports. Air traffic control itself – in Germany DFS – supplies the figures on how many approaches it can safely separate in an hour.

Why the runway is almost always the bottleneck

Terminals, aprons and baggage systems can be expanded, sometimes even within a few years. A new runway, by contrast, often takes decades from first planning to opening – if it comes at all. That’s why the runway system is the real bottleneck at almost all major airports. How many movements a runway can handle depends on four factors.

1. Runway occupancy time

A landing aircraft blocks the runway until it has left it via an exit taxiway. A departing one blocks it from lining up until shortly after liftoff. High-speed exits that branch off the runway at an angle shorten this time noticeably. Every second less that an aircraft spends on the runway is worth its weight in gold in capacity over the hour.

2. Separation on approach

On final approach, aircraft have to keep minimum distances. Behind large, heavy aircraft these distances are greater, because wake turbulence can endanger following aircraft. If a regional jet lands behind an Airbus A380, it needs considerably more air than between two medium-haul jets. A high share of long-haul aircraft therefore lowers the possible number of landings per hour. The background is in the article Wake turbulence and separation.

3. Mix of takeoffs and landings

On a single runway, takeoffs can be cleverly slotted into the gaps between landings. A good controller gets more out of one runway this way than if only landings or only takeoffs took place. This mix is demanding, though, and only works if the rhythm on approach is clean.

4. Weather and runway direction in use

In poor visibility, larger distances apply, because aircraft fly instrument approaches and the runway has to stay clear longer. Strong wind, thunderstorms or a runway direction in use that makes unfavorable use of the runway system reduce capacity further. How wind decides the direction of operations is shown in the guide Understanding the runway direction in use at an airport; how instrument approaches work is in ILS approach explained.

Runway systems compared

How much an airport can handle depends heavily on how its runways are laid out relative to each other. The most important basic forms:

Runway system	Typical example	Operation	Effect on capacity
A single runway	Gatwick (in normal operations)	takeoffs and landings on the same runway	severely limited, efficiency depends on taxiways and rhythm
Closely spaced parallel runways	Düsseldorf (about 500 m apart)	runways dependent on each other, often only as an alternate or additional runway	little more than one runway
Widely spaced parallel runways	Munich (about 2,300 m apart)	independent takeoffs and landings on both runways	nearly double the capacity of one runway
Crossing runways	Hamburg (05/23 and 15/33)	intersection area used alternately	well below two independent runways
Combination of several systems	Frankfurt (three parallel runways plus runway 18)	mix of separate landing and takeoff runways	high capacity, but complex dependencies

The runway numbers in the table indicate the orientation of the runways. If you want to know how the designations with L, C and R come about, read the article Runway designations at airports.

Why spacing matters so much

Parallel runways may only be used completely independently of each other for approaches if they are far enough apart. ICAO specifies minimum runway centerline spacings for this, which depending on procedure and radar monitoring are well over a kilometer. Frankfurt even needed an exemption for the northwest runway, because its distance from the old north runway, at about 1,400 meters, is just below the required value. Below that, approaches to both runways have to be coordinated with each other, which pushes capacity down considerably. With very closely spaced runways, simultaneous operation is often not possible at all.

German and European examples

Frankfurt: capacity through the northwest runway

Frankfurt Airport has four runways: the three parallel runways 07R/25L, 07C/25C and 07L/25R as well as runway 18 to the south. The northwest runway (07L/25R) is used only for landings, runway 18 only for takeoffs. Before it opened, Frankfurt was at about 83 movements per hour in 2010. With the new runway from October 2011, capacity was raised step by step, and since 2018 the declared capacity has been 104 movements per hour. The jump came mainly from the new runway allowing independent parallel approaches for the first time. In the long term, after the expansion with Terminal 3, up to 126 movements per hour are considered possible.

For you at the fence this means: traffic is spread across several runways, and what you see from which spot depends heavily on the runway direction in use. An overview of the locations is given by the Frankfurt guide; from the Zeppelinheim viewing platform at the east end of the grounds you mainly see the landings on the south runway 25L during westerly operations.

Munich: two independent parallel runways

Munich Airport has two 4,000-meter runways, 08L/26R and 08R/26L. Their axes are about 2,300 meters apart, and the thresholds are also staggered. Under ICAO rules, that lets both runways be operated independently. The slot capacity is 90 movements per hour. A third runway was meant to raise capacity to 120 movements; it was approved by planning decision in 2011, but a Munich citizens’ referendum stopped the project for the time being in 2012. How to experience operations on site is described by the Munich guide and the fact sheet on the visitors’ hill (Besucherhügel).

Hamburg: two runways that cross

At Hamburg Airport, runways 05/23 and 15/33 cross. Because the intersection area can only be used by one aircraft at a time, both runways together manage at most about 48 takeoffs and landings per hour. On top of that come runway use rules for noise protection and night flight restrictions between 11 p.m. and 6 a.m. That makes Hamburg manageable for spotters: the rhythm is calmer, and with knowledge of the preferred runways it’s easy to plan. More in the Hamburg guide and at the Affenfelsen.

Düsseldorf: closely spaced parallel runways

Düsseldorf Airport has two parallel runways, 05R/23L and 05L/23R, but only about 500 meters apart. Simultaneous independent operation is therefore not possible. On top of that comes the so-called Angerland settlement of 1965, which legally fixes the capacity and the ban on night takeoffs. In 2015 the airport applied for a change to its operating permit that provides for up to 60 coordinated movements per hour at peak times; the procedure was controversial for a long time. A spotter’s view of this airport is offered by the Düsseldorf guide.

London Heathrow: segregated operations at the limit

London Heathrow Airport has two parallel east-west runways, 09L/27R and 09R/27L. Instead of an hourly figure, it mainly works with an annual cap of 480,000 movements, and the two runways are more than 98 percent utilized. Heathrow generally operates segregated: one runway is used for landings, the other for takeoffs. During westerly operations the runways swap roles daily at 3 p.m. local time, so that residents under the approach routes have fixed quiet periods. During easterly operations there has been no such swap so far. If you know that, at spots like Myrtle Avenue you’re at the right runway at the right time. More in the Heathrow guide.

London Gatwick: the textbook case of the single runway

London Gatwick Airport shows what a single runway can do. The main runway 08R/26L counted as the world’s busiest single-runway operation until 2017, with up to 55 movements per hour. The parallel northern runway lies only about 200 meters beside it and has so far served as an alternate runway when the main runway is closed. In 2025 the British government approved plans to shift the northern runway and use it regularly. Spotter info on it is offered by the Gatwick guide.

Mixed or segregated operations

With several runways, the question arises how to divide them up. Both variants have their logic.

Which variant an airport runs depends not only on technology but also on permits and agreements with the surrounding area. For you, that means: with segregated operations it’s clear where landings take place – and where you should set up with your telephoto lens.

When capacity suddenly drops

Declared capacity applies to normal conditions. In everyday operations there are many reasons why an airport can handle less at short notice:

• Runway closures and construction work: If a runway is out, capacity collapses and traffic runs over unfamiliar routes. For spotters that can be an opportunity, as the article Runway closures and construction work shows.
• Poor visibility: In fog, larger distances apply, and air traffic control reduces the number of approaches.
• Thunderstorms and strong crosswinds: Individual runways or directions of operation become unusable.
• Airspace bottlenecks: Even if the airport had room, the surrounding airspace can be saturated. Then European network management at Eurocontrol regulates the inflow via delay restrictions.
• Night rules: At off-peak times, restrictions apply that let traffic wind down. More in Night flight ban at German airports.

What the numbers mean for your spotting plan

A declared capacity of 104 doesn’t mean you see 104 aircraft every hour in Frankfurt. At hubs, traffic comes in waves: first a dense sequence of feeders lands, then the connecting flights depart. In between there are quieter phases. How these waves arise and how you use them is described in the article Understanding hub waves.

What to watch out for

• Declared capacity is not live traffic. The number describes an upper limit for planning, not the movements in a particular hour.
• Don’t confuse hourly and annual figures. Heathrow works with an annual cap, German airports mostly with hourly values. The two can’t be compared directly.
• Two runways are not double the capacity. Spacing, crossings and mode of operation decide whether a second runway can really be used independently.
• Values change. Declared capacities are set anew for each flight schedule period. The figures given here reflect the state at the time of research.
• Safety before results. Even if it gets hectic in the peak hour: stay on public areas. What applies around the fence and the approach path is summed up in Is plane spotting allowed?

Conclusion

An airport’s capacity is no coincidence but the result of runway layout, separation, mode of operation and rules. Declared capacity turns it into a binding number for slot allocation. Frankfurt shows how much an additional, independently usable runway brings, Hamburg how crossing runways slow things down, and Heathrow what it looks like when an airport runs at its limit permanently. If you know these connections, you read operations at the fence like a timetable.