Demand forecasting
Reset the booking reference when capacity changes
Historical curves do not become useless after a capacity change, but they cannot be carried forward untouched. Comparability needs to be rebuilt explicitly.
Start with a capacity-change record
Aircraft assignment, frequency, departure time, and the opening of sales can all reshape a booking curve. I record the change, its scope, and the information available at the time before judging whether it altered seats for sale, traveller choice, or the observation window.
Rebuild the reference around comparable conditions
Earlier flights still contain useful season, weekday, and lead-time information. Capacity differences need a separate treatment. Raw cumulative bookings will naturally favour the larger aircraft, so I would keep them beside sold-seat share and pickup by fare level rather than asking one measure to explain every change.
| Condition | Review question |
|---|---|
| Capacity | Are seats for sale and cabin configuration comparable? |
| Frequency | Did demand redistribute across frequencies on the same route? |
| Schedule | Could departure or arrival timing change traveller choice? |
| Selling window | Do the comparison start and sales-opening rules match? |
Separate demand movement from capacity movement
Keep one view in raw cumulative bookings to describe sales progress, and another normalised to seats for sale to locate the flight after the capacity change. If they point in different directions, that disagreement is useful. It says capacity and demand are both shaping the result.
Keep each forecast tied to its assumptions
Each update should retain its reference set, capacity assumptions, known changes, and decision date. The review then sees a sequence of explainable forecasts rather than one overwritten figure. Version history rarely makes a worksheet prettier, but without it variance analysis becomes hindsight.
Limits of a route-level reference
A single-flight curve cannot capture connections, nearby airports, competitors, or network contribution. A revised reference makes the forecast comparison more honest; frequency, aircraft, and pricing decisions still need the wider network view.