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How airliners avoid conflict zones

On the seat-back map your flight to Tokyo curves far to the south, then bends again. It is not the pilots taking the scenic route. Somebody decided, weeks before you boarded, that the shortest line was not an option.

  • Curious
  • General aviation
  • 7 min read
  • 25 October 2026

The question

A few years ago a flight from Frankfurt to Tokyo took about 11 and a half hours. Today the same flight on a European airline takes two hours longer or more. The aircraft are not slower. The route is longer, because a large part of the map is now off limits.

The shortest path is a curve

On a globe, the shortest line between two cities is a great circle. From Europe to Japan it runs north-east over Russia and Siberia. On a flat map that line looks curved, which is why routes on seat-back screens never look straight. When part of that line becomes unavailable, the airline has to find the next best curve around it.

Two different kinds of “no”

1. The airspace is closed

Every country owns the airspace above its territory, and only that country can open or close it. Ukraine has been closed to civil flights since the Russian invasion in February 2022. The same month, the European Union closed its airspace to Russian aircraft and Russia closed its own to European airlines in return. European airlines had already been told to stay out of Belarus in 2021, after a Ryanair flight was forced to land in Minsk.

A closure is published as a NOTAM, a notice to air missions, and air traffic control simply will not accept a flight plan through it.

2. The airspace is open, but dangerous

This is the harder case. A country at war may keep its airspace open, while missiles, drones or air defence systems are active below. On 17 July 2014, Malaysia Airlines flight MH17, a Boeing 777 flying from Amsterdam to Kuala Lumpur, was shot down over eastern Ukraine at cruising altitude. All 298 people on board died. The airspace at that height was open.

After MH17, Europe set up a system to warn airlines about such places.

Who decides the route

INFORMATIONgovernments, intelligence, NOTAMs EASAbulletin (CZIB): a recommendation THE AIRLINEown risk assessment, picks the route PILOTSflight plan, NOTAM briefing, fly it The country that owns the airspacecan close it at any time.
EASA does not close airspace: it recommends. The final choice of route belongs to the airline.

EASA, the European Union Aviation Safety Agency, runs the EU Conflict Zone Alerting System, active since 2016. Together with the member states it collects information and, when a place looks dangerous for civil aircraft, publishes a Conflict Zone Information Bulletin (CZIB). A bulletin says which airspace is affected, up to what altitude, and until when.

A bulletin is a recommendation to airlines. The airline then makes its own risk assessment: its security team reads the bulletins, the NOTAMs and its own sources and decides which routes it will fly. Its dispatchers turn that into a flight plan. National authorities can go further: the US FAA, for example, prohibits American airlines from flying in some airspaces outright.

Here is what EASA had in force at the start of October 2026: Iran (do not fly in the Tehran region at any altitude), Iraq, Syria, Lebanon, the Persian Gulf and the Gulf of Oman, and, new on 30 September, part of the Jeddah region in Saudi Arabia. Most of them are valid until 16 November 2026 and are reviewed regularly, so the list changes often.

See the detour

Pick a route. The map shows the airspace closed to European airlines and the areas covered by EASA bulletins, with the numbers for each choice.

What a detour costs

About 1,900 extra kilometres via Central Asia means more than two extra hours in the air. For a large twin-engine airliner that is around 14 tonnes of extra fuel and about 45 tonnes of extra CO₂, on every single flight. It also means fewer passengers or less cargo when the aircraft is near its maximum take-off weight, longer working days for the crew, and higher ticket prices.

Airlines from countries that did not close their airspace to Russia can still use the shorter line, so the same city pair can take them less time. That is why some European airlines have dropped routes to Asia altogether.

What you see from your seat

  • A route that zig-zags along borders: the airline is following an approved corridor, not taking a shortcut.
  • A technical stop: on very long detours a heavy aircraft may need to stop for fuel, or carry fewer passengers.
  • A sudden change of plan: if a new bulletin or NOTAM appears, flights already planned can be rerouted, delayed or cancelled within hours.

Common myths

“Flying higher is always safe”

No. MH17 was at cruising altitude. Some weapons reach the heights airliners fly at, which is why bulletins often say “at all altitudes”.

“EASA closed that airspace”

Only the country that owns the airspace can close it. EASA recommends; the airline decides.

“The pilots choose the detour on the day”

The route is planned beforehand by the airline's dispatchers. The captain checks it, and can refuse a route that looks unsafe.

“If the route is open, it is safe”

Open only means air traffic control will accept the flight. Every airline still has to judge the risk for itself.

Test yourself

1. Who can close a country's airspace?

Only that country. EASA and other agencies can only recommend that airlines stay away.

2. What is a CZIB?

A Conflict Zone Information Bulletin from EASA: a recommendation to airlines about a dangerous area, with its altitudes and how long it is valid.

3. Why do European flights to Japan take longer today?

Russian airspace is closed to European airlines, so they fly a longer route via Central Asia or over the Arctic.

Read next: a day with air traffic controllers

The people who keep aircraft apart, and how a flight passes from one controller to the next, with a radar game.

Read ›

FlightDesk Aero articles are for information and training. Conflict-zone advice changes often: for current bulletins see the EASA website. This article explains how aviation works and takes no political position.