Online coding and Python classes in Crawley

The learner downloads twelve monthly files from the Civil Aviation Authority, keeping the Gatwick row of Table 03 for air transport movements and Table 09 for terminal passengers. Dividing one by the other month by month gives passengers per movement: 157.6 in January, the lowest, rising to 177.6 in August, the highest, at the summer peak. The obvious next step is to average those twelve monthly figures. Python returns 164.13.

But the CAA also publishes Gatwick's annual totals, 42,769,164 passengers and 259,391 movements, and dividing those gives 164.88. The two answers differ because August, with more flights, should count for more than January, and a plain average of months ignores that. The average of averages treats a quiet month and a busy month as equals. At one airport the gap is under one passenger per flight, small enough that a careless program would never be caught.

Across the country the same slip becomes huge. In July 2025 the CAA lists 45 UK airports with flights. Averaging their 45 ratios gives 81.6 passengers per movement, because tiny airfields count as much as Heathrow: Biggin Hill manages 0.9 passengers per movement, Gatwick 172.1 and Heathrow 192.4. Weighting each airport by its flights gives 150.6, nearly double. The learner also notes a data trap: adding up Table 05's three movement categories for December does not match Table 03's published total, so the program uses published totals and never rebuilds them from parts.

Choosing the average that fits the question is precisely why coding still repays Crawley teenagers in 2026. The longer argument is in why teenagers should still learn to code in 2026.