Friday high, Saturday low: the weekend gap is widening

The week in numbers

Between Monday 5 October and Sunday 11 October our receivers logged 15,326 different aircraft near the 966 airports where we saw traffic. Counted per airport and per day, that is 24,265 sightings, 327 more than the week before (23,938). We took slightly fewer snapshots this week, 81,121 against 82,226, so per snapshot the sky was 2.7 percent busier. A normal autumn week in total, then, but an unusual one in its shape.

Friday 9 October was the busiest day with 3,913 aircraft, and Saturday 10 October the quietest with 2,667. Both are extremes for the four weeks we show here: no day since mid-September had more aircraft than this Friday, and none had fewer than this Saturday. The two sit 47 percent apart, where last week the gap between the busiest and the quietest day was 30 percent. Tuesday (3,168) and Thursday (3,213) were the quiet weekdays.

Saturday keeps slipping: four weeks in a row

Last week we promised to watch whether the Saturday dip would stay at 30 percent as the autumn schedules settled. It did not stay; it grew. Put the past four weeks side by side and a pattern appears. The average weekday rose a little every week, from 3,385 aircraft in mid-September to 3,481 now. Saturday went the other way every week: 3,087, then 2,965, then 2,909, and now 2,667. Measured against its own weekdays, Saturday fell from 91 percent to 77 percent in four weeks. Sunday did not follow: it stayed between 3,037 and 3,247 throughout.

Fewer snapshots do not explain it. Saturday 10 October had 11,405 snapshots, 3 percent fewer than Friday; per snapshot the drop from Friday to Saturday is still 30 percent. And per snapshot Saturday still fell four weeks in a row, from 26.2 to 23.4 aircraft per hundred snapshots.

We do not know why, and the data alone cannot tell us; we name the shift and leave the cause open. One thing it is not: the airlines’ winter timetable, which only starts on 25 October. If the gap widens again next week, it becomes the story of the autumn. If Saturday bounces back, it was three weeks of noise and we will say so.

What held and what did not: Canada, France, Spain and the fleet

Last week we flagged two moves and refused to call them trends: Canada down 13 percent, France up 23 percent. Neither survived. Canada came back up 3.1 percent to 1,101 sightings, so its dip was noise. France gave back most of its rise and ended 4.8 percent lower at 340. That is exactly why we wait a week before we call anything a story. The United States, with 299 of the 966 airports, was up 5.7 percent to 12,787 sightings and remains just over half of everything we see.

The number that jumps out is Spain, down 41 percent. That is not Spain; it is one airport. We normally do not publish week-on-week changes for single airports, because with about three snapshots a day they are mostly noise, but this one is far outside noise and explains the whole Spanish figure: our count around Madrid-Barajas fell from 201 to 38 with almost the same number of snapshots, while the other Spanish airports did not move like that. The airlines based in Madrid fell with it. We cannot tell from the data whether Madrid itself was that much quieter or our receivers saw less there, and a drop this large and this concentrated is one we treat as a measurement question first. Until we know, read the Spanish total with care. Two smaller notes: the United Kingdom’s 10 percent fall is partly us, since we polled Heathrow 21 times instead of 24, and corrected for snapshots the fall is 7.6 percent; New Zealand’s 25 percent rise came with fewer snapshots, not more, so that one is real for the week.

American Airlines widened its lead at the top: 1,237 sightings, up 12.8 percent, ahead of Southwest (1,119) and Delta (1,101), where last week the three were within 52 of each other. Alaska Airlines (up 17 percent to 351) and the business jet operator Flexjet (up 41 percent to 121, just outside this list) had the largest rises among the regulars; Swiss (down 17 percent to 109) the largest fall. Ryanair, the first non-American name, slipped 6.3 percent to 358. The third thing we were watching, the gap between the Airbus A320 and Boeing 737 families, barely moved: counting the five main variants of each, we saw 3,146 A320-family aircraft against 2,913 of the 737 family, a lead of 233 for Airbus after 248 last week. The Boeing 737-800 remains the single most-seen type with 1,327 aircraft, and the Cessna 172 keeps its fifth place with 623.

What to watch next week

Three things again. Saturday: if it drops below 77 percent of the weekday average once more, the widening gap is the story of the autumn; if it bounces back, it was noise. Madrid: whether our count there returns to its usual level, which would tell us the fall was on our side and not in the Spanish sky. And American Airlines: whether its 13 percent rise holds while the other big names move by a few percent. The next article covers week 42, 12 to 18 October.