Punctuality figures are published and compared, and the measurement rests on a definition that airlines partly control.
The definition
Arrival within a defined number of minutes of scheduled time.
Which is generally fifteen minutes in most reporting regimes.
A flight fourteen minutes late counts as on time.
Schedule padding
Scheduling more time than a flight requires.
Which improves punctuality statistics without any operational improvement.
Scheduled block times have lengthened over decades on many routes, which is documented.
What is measured
Gate departure and arrival rather than take-off and landing.
Which means time spent taxiing counts differently from what passengers experience.
A flight can push back on time and sit on a taxiway for an hour.
Cancellations
Excluded from punctuality figures entirely.
Which means an airline cancelling delayed flights improves its statistics.
Cancellation rates are published separately and should be read alongside.
Attribution of delays
Airlines report causes, categorised as airline-controlled, weather, air traffic control or other.
Which affects compensation liability.
Attribution is partly self-reported, and disputes about categorisation are common.
Compensation frameworks
Several jurisdictions require compensation for delays above thresholds, with exemptions for extraordinary circumstances.
Which is where attribution matters financially.
Case law has narrowed what counts as extraordinary considerably.
Airport and route effects
Congested airports and short turnarounds produce delays regardless of airline.
Which makes comparing airlines without accounting for route networks misleading.
Using the data
Route-specific punctuality is more useful than airline averages.
Published data allows checking a specific flight number's history, which is worth doing for tight connections.
Connection risk
Minimum connection times are set by airports and airlines.
Which are frequently optimistic at busy hubs.
Booking a single ticket rather than separate ones determines whether the airline is responsible for a missed connection.
Aircraft rotations
Delays propagate through the day as aircraft fall behind schedule.
Which is why early departures are more reliable than late ones.
This pattern is visible in published punctuality data by time of day.
Baggage performance
Mishandled baggage rates are published separately.
Which vary substantially between airlines and airports.
Connection-heavy itineraries carry higher risk mechanically.
Claiming compensation
Applications can be made directly to the airline free of charge.
Which agencies charge a percentage to do.
Regulators publish guidance and template forms.
Reading the data
Route and time-of-day specific figures are published and are far more useful than airline averages.
Air traffic control constraints
Capacity limits at airports and in airspace produce delays outside airline control.
Which is why attribution categories exist.
Industrial action and staffing shortages in air traffic control have produced substantial disruption in several regions.
Weather
Generally treated as extraordinary for compensation purposes.
Which is contested at the margins, since some weather is foreseeable and mitigable.
Case law has narrowed the exemption over time.
Slot systems
Airport capacity is allocated in slots that airlines hold and must use.
Which has produced flights operated at low occupancy purely to retain slots.
Rules on this were relaxed during periods of reduced demand and have since been restored.
Passenger experience
Duty of care obligations — meals, accommodation, rerouting — apply during long delays in several jurisdictions.
Which are separate from compensation and are not affected by the cause of the delay.
Airlines frequently mention compensation and not duty of care.
Where the data is
Regulators and airports publish punctuality data openly, generally monthly and by route.
Why airlines pad schedules
Published punctuality affects booking decisions and, in some markets, regulatory reporting.
Which creates an incentive to lengthen scheduled times.
The consequence is longer journeys on paper and better statistics, which is a rational response to how performance is measured.
What travellers can control
Earlier departures, longer connections, single tickets and hand luggage only for tight itineraries.
A closing observation
A measure that airlines can improve by lengthening their own schedules is measuring something, and it is not what passengers experience.
Route-level data and journey times, both published, answer the practical question better than the headline punctuality figure ever will.
Seasonal and hub effects
Summer peak periods and weather-prone seasons produce systematically worse performance.
Which means comparing an airline's summer figures with another's winter figures is meaningless.
Published data allows like-for-like comparison by month and by route.
Rebooking rights
Passengers are generally entitled to rerouting or a refund when a flight is cancelled.
Which is separate from any compensation and applies regardless of cause.
Airlines frequently offer only a refund, and the alternative should be offered.
A final note
A statistic an airline can improve by changing its own timetable is measuring the timetable as much as the operation.
Route-level published data answers the practical question — will this flight get me there — considerably better.
Airport and regulator websites publish it monthly, free of charge, broken down by carrier and route.
Checking a specific flight number before booking a tight connection takes a minute and is genuinely predictive.