They have already started canceling some flights in specific situations, and there is no single universal date when “they” will start, because cancellations depend on which airline, route, and disruption you’re talking about.

What’s happening right now

  • Major airlines regularly adjust schedules, and some routes are being permanently cut starting in early 2026, such as certain Delta flights that stop operating in January 2026.
  • In the US, government and air-traffic issues recently led regulators to order airlines at about 40 busy airports to cut a percentage of flights on specific dates (for example, phased cuts starting around early November during a shutdown).
  • In disruption zones (like after severe weather or regional crises), airlines sometimes cancel hundreds of flights over a short window, then gradually resume service as conditions stabilize.

How to tell if your flight is at risk

Because cancellations are very route‑ and date‑specific, the timing for “when they will start cancelling flights” depends on:

  • Which airline you’re flying (American, Delta, Southwest, United, etc.), since each one publishes its own operational updates.
  • Which airport/region you’re departing from, especially if it’s one of the high‑impact or recently disrupted airports. Certain hubs have been asked to cut a fixed percentage of flights during constrained periods.
  • The travel window (for example, holiday peaks or immediately after storms or political issues), when proactive cuts are more common to avoid chaotic day‑of cancellations.

Practical steps you should take

  • Check your airline’s app or website frequently; they usually post schedule changes and rebooking options there first.
  • Turn on flight alerts via tools like flight‑tracking apps or your airline’s notifications so you see any cancellation or delay as soon as it is logged.
  • If you’re traveling into or out of a region that’s been in the news for operational disruptions, assume there is an elevated risk of cancellation and keep flexible backup options in mind.

In forum discussions, travelers often phrase this as “when will they start cancelling flights,” but the reality is that cancellations roll out in waves tied to specific events (staffing, weather, shutdowns) rather than a single global start date.

TL;DR: Cancellations are already happening in targeted ways and will continue whenever demand, staffing, weather, or government orders require them; the only reliable way to know about your flight is to monitor your airline and airport for your exact dates.

Information gathered from public forums or data available on the internet and portrayed here.