When, where and how to fly

Success is the share of an airline's scheduled flights on a route that actually operated and arrived less than 15 minutes after the scheduled gate time. A cancelled flight counts as a failure, so an airline that cancels its late flights rather than running them cannot rank well by doing so. Only airlines with at least 365 flights on a route are ranked, which is about one a day.

The best departure time and day come from that airline's own flights on the route where there are enough of them, and from every airline on the route otherwise, which the results mark. Time, day and airline are measured separately, not in combination, so treat the suggested plan as three good odds stacked together rather than a single measured figure.

For a trip with a connection, use the connection risk calculator. Every route page has the same five-option table for its own trip, and the same route, different airline guide explains how much the carrier choice can matter. Definitions are on the methodology page.