Why flight paths curve: great circles on a flat mapThe shortest way between two airports is a great circle, which on most maps looks like a bend. Why that is, how much it saves, and why real tracks still leave it.Usable range: why the brochure figure is not the one that mattersAn aircraft's published range is quoted in conditions no flight meets. What reserves, payload and wind take off it, and the figure Overfly checks a route against.Equal-time points and ETOPS, explainedWhy a twin-engine aircraft has to stay within so many minutes of an airport, how the worst point on a leg is found, and the trap a still-air assumption sets.How wind changes block time, and why eastbound is quickerThe jet stream makes some flights an hour shorter one way than the other. How much, in which months, and what an average can and cannot tell you.Tech stops: where long flights stop, and whyWhen a leg is longer than the aircraft's range, it stops for fuel on the way. How a good stop is chosen, the famous ones, and how Overfly suggests them.The Pacific Clipper: the long way home, 1941–42Why Overfly's map opens on a twelve-leg route from Auckland to New York: a Pan Am flying boat cut off by war, and its flight home the other way round the world. For reference and planning interest. Not for operational flight planning. © 2026 Overfly.Flights