What does NOTAM stand for?

NOTAM stands for Notice to Air Missions (formerly Notice to Airmen). It is an official notice issued by aviation authorities to alert pilots and airlines about potential hazards or changes along a flight route or at an airport.

Can a NOTAM cancel my flight?

Yes. NOTAMs related to runway closures, airspace restrictions, or airport equipment failures can lead to flight delays or cancellations. However, most NOTAMs are informational and don't directly affect passengers.

How can I check NOTAMs for my flight?

You can check active NOTAMs on notaminfo.com or through your country's aviation authority. FlightGuard automatically monitors NOTAMs for your route and factors them into the flight risk score.

What are NOTAMs and how do they affect your flight?

26 March 2026

What are NOTAMs and how do they affect flights?

If you’ve ever tried to understand why your flight was inexplicably delayed — clear weather, no strikes, everything apparently normal — the answer might lie in a five-letter acronym: NOTAM. These notices, virtually unknown to passengers, are one of the most important tools in civil aviation and can directly affect your flight.

What a NOTAM is

NOTAM stands for Notice to Airmen (or, in updated ICAO terminology, Notice to Air Missions). It’s a formal notice published by aeronautical authorities to inform pilots and aviation operators of conditions that may affect flight safety.

NOTAMs are published by the aeronautical authority of each country and are accessible globally through the ICAO system.

Each NOTAM has:

A unique identification code
A validity period (start and end date)
The affected area (airport, airspace zone, route)
The nature of the notice (closure, restriction, hazard, information)

Concrete examples of NOTAMs

NOTAMs cover a huge variety of situations. Here are the most common and their impact on flights:

Runway closure for works

One of the most frequent NOTAMs. The airport reduces operational runways for maintenance — resurfacing, light repairs, marking works. If an airport with two runways closes one, takeoff and landing capacity halves. Consequence: reduced slots, longer waiting times, possible delays.

Military exercises

Airspace isn’t just for civilians. Air forces across Europe regularly conduct exercises requiring the temporary closure of airspace portions. Civil flights must detour around the closed zone, extending route and flight times. In Europe this happens more often than you’d think, especially over coastal areas and Eastern Europe.

Drone presence

An increasingly frequent NOTAM in recent years. Reports of an unauthorised drone near an airport can cause the temporary suspension of all operations. The most notorious case: in December 2018, London Gatwick airport was closed for nearly 36 hours due to drone sightings, affecting over 140,000 passengers.

Volcanic activity

Volcanic ash is extremely dangerous for aircraft engines. When a volcano erupts, NOTAMs are issued that can close entire portions of airspace. The 2010 eruption of Iceland’s Eyjafjallajokull generated the largest European airspace closure since World War II: over 100,000 flights cancelled in a week.

VIP transit

When a head of state or high-level dignitary travels by air, temporary restrictions are imposed on the surrounding airspace, known as TFR (Temporary Flight Restriction). These can cause brief delays at affected airports.

Airport conditions

NOTAMs can also cover local situations: an instrument landing system (ILS) out of service, non-functioning runway lights, closed taxiways. These conditions may not cause delays under normal circumstances, but become critical in poor visibility or bad weather.

How NOTAMs are published

NOTAMs follow a standardised international format and are published through various channels:

AIS (Aeronautical Information Service) of each country
ICAO internationally
EAD (European AIS Database) for Europe
Public sites like notaminfo.com

The traditional NOTAM format is notoriously difficult to read — a mix of abbreviations, codes and coordinates that only aviation professionals decode easily. Here’s a real example:

A0123/26 NOTAMN
Q) LIMM/QMRLC/IV/NBO/A/000/999/4527N00912E005
A) LIMC B) 2603150600 C) 2603152000
E) RWY 35R/17L CLSD DUE TO MAINT

Translated: runway 35R/17L at Milan Malpensa airport (LIMC) is closed for maintenance from 06:00 to 20:00 on 15 March 2026. Clear, right? That’s why passengers don’t read NOTAMs.

How NOTAMs affect your flight

The impact of NOTAMs on flights depends on the nature of the notice:

Direct impact (delays likely)

Runway closure at departure or arrival airport
Airspace restrictions along the route
ILS system out of service in poor visibility conditions
Operations suspended for drones or volcanic activity

Indirect impact (delays possible)

Partial taxiway closure (slows ground movements)
Route deviations for military exercises (longer flight)
Night restrictions at airports with curfews (limits operational window)

Minimal impact

Informational NOTAMs (e.g. crane under construction near the airport)
Changes to instrument procedures that don’t reduce capacity

Why passengers know nothing about them

NOTAMs are a tool for aviation professionals. They’re not communicated to passengers because:

They’re technical and difficult to interpret
Many are irrelevant to any single flight
Airlines handle NOTAM planning internally

The problem is that when a NOTAM causes a delay, the airline often communicates only a generic “delay for operational reasons” without explaining the actual cause. The passenger is left in the dark.

How to monitor NOTAMs for your flight

If you want to know if there are active NOTAMs that could affect your flight, you have some options:

Check notaminfo.com: enter the ICAO code of the airport (e.g. EGLL for London Heathrow, LIMC for Milan Malpensa) and you’ll see all active NOTAMs
Use aviation authority tools: each country’s aviation authority publishes NOTAMs
Monitor NOTAMs automatically: FlightGuard analyses active NOTAMs for the departure and arrival airports of each flight and includes them in the risk score calculation, so you don’t have to decipher aviation jargon yourself

NOTAMs in the context of flight risk

A single NOTAM rarely causes a cancellation (unless it involves a complete airport closure). More often, NOTAMs contribute to an overall risk picture: a runway closed for works combined with forecast thunderstorms and high traffic can generate significant delays that none of the three factors alone would have caused.

That’s why assessing a flight’s risk requires cross-referencing multiple factors: weather, NOTAMs, ATC delays, route history and the airline’s situation.

Sources

Want to know if your next flight is at risk? Check the risk of your flight on FlightGuard.