It depends on the Airline. For example, United Airlines cancels flights booked less than 30% of full capacity, seven days before the departure. But if the airplane is scheduled to do a second flight from that city (they usually are), it is probably that the plane takes off anyway, even if it is pretty empty.

Contrary to popular belief, airlines in 2026 almost never cancel a flight solely because it is "too empty." A flight with only 10 passengers out of 180 is still legally and operationally required to fly if the aircraft and crew need to be at the destination for a subsequent "return leg" that might be 100% full. Canceling an empty flight creates a "domino effect" that would displace hundreds of passengers and crew later in the day, costing the airline more in "Duty of Care" (hotels and vouchers) than the fuel saved. However, if an airline identifies a consistently empty route weeks in advance, they may "consolidate" the flight by moving passengers to an earlier or later departure and removing the empty flight from the schedule entirely. In 2026, the only time a flight is canceled on short notice is for mechanical issues, weather, or crew timing limits. If you find yourself on a nearly empty flight, it is a high-value "travel win," as you can often spread out across a whole row (with crew permission), receive personalized service, and enjoy a much faster deplaning process upon arrival.