Your flight is holding in a racetrack loop 50 miles from the airport and the gate agent has no explanation. Chances are, the answer lives in a NOTAM — a Notice to Airmen (or Missions), one of thousands of time-critical alerts issued daily by aviation authorities like the FAA and Eurocontrol. These notices flag everything from runway closures and out-of-service landing systems to GPS jamming, construction cranes near approach paths and military exercise zones. Passengers rarely see them; pilots and dispatchers wade through them before every single flight.
Why should a holidaymaker care? Because NOTAMs quietly shape your journey. A short-notice runway closure at a hub like London Heathrow or New York JFK means inbound aircraft enter holding stacks, burn contingency fuel and force dispatchers to decide between waiting or diverting. The knock-on effects — missed connections, expired crew duty limits, cascading delays across an airline's network — all trace back to a few lines of coded text.
The system's flaws are well documented. In 2017, Air Canada Flight 759 nearly landed on a taxiway at San Francisco International, coming within 14 feet of four fully loaded passenger jets. The NTSB found the crucial notice declaring the parallel runway closed was buried on page eight of a 27-page briefing packet, lost among low-priority items about unlit lawnmowers. On long-haul routes, briefing packages regularly exceed 30 pages of dense teletype code, and even automated Electronic Flight Bag software can't fully filter the clutter.
Change is coming, though. A data standard called AIXM 5.1, developed by ICAO and Eurocontrol, turns raw text into structured information with precise coordinates and time windows. That allows tools like Simple Flying's live Flight Tracker to render NOTAMs as colour-coded shapes on a radar map — restricted airspace as shaded polygons, closed runways highlighted, hazard markers at exact GPS points. You can watch a holding pattern form in real time and actually understand why it's happening. A recent example: a notice restricting certain approach procedures at France's Saint-Dizier air base, home to Rafale fighters, displays as a clear five-nautical-mile boundary rather than a wall of military acronyms.
For aviation-curious travellers, it's a genuinely useful window into operations that used to stay behind the flight deck door. For everyone else, it's a reminder that when your flight circles instead of landing, there's usually a documented, official reason — even if it never made it to the departure board.
