Methodology

1. Flight distance and flight time estimates

We calculate route distance from airport coordinates using a great-circle (Haversine) model. This gives the shortest theoretical path over Earth's surface, not the exact path flown by a specific airline.

We then convert distance into a gate-to-gate time range using distance-banded cruise speed heuristics plus additional overhead for taxi, climb, descent, and approach. This is intentionally a range, not a single minute value, because real operations vary by aircraft, routing, winds, airport congestion, and runway assignment.

• Short-haul routes use lower effective average speeds because climb/descent phases dominate.
• Long-haul routes use higher effective average speeds because cruise makes up more of total time.
• A fixed operational overhead is added to move from airborne time toward realistic gate-to-gate estimates.

2. Time zone differences and DST handling

Time zone calculations use IANA time zone identifiers assigned to each airport (for example, Europe/Londonor America/New_York). When a date is supplied, the app calculates the offset difference for that date so daylight saving transitions are reflected in the result.

This is important because offset differences can change during the year, and two locations may switch daylight saving time on different dates (or one may not observe DST at all).

3. Jet lag severity and adjustment plans

Jet lag severity is estimated from the number of time zones crossed and direction of travel (eastbound vs westbound). The adjustment plan is a heuristic schedule intended for general planning: sleep timing, light exposure windows, and caffeine cutoffs are generated from common circadian adaptation patterns.

The model is useful for trip preparation and expectations setting, but it is not individualized medical advice. People differ significantly in chronotype, sleep debt, health status, and response to travel.

4. What the route pages optimize for

Each route page is designed to answer common traveler questions quickly (flight time, time difference, jet lag impact) and then provide planning context (recovery timeline, business-hours overlap, assumptions, related routes, and FAQs). We prioritize practical planning utility over airline schedule replication.

5. Limitations and known sources of variation

• Airline schedules may differ due to block-time padding and fleet-specific performance.
• Winds and routing can materially shift long-haul flight duration (especially oceanic routes).
• Government time-zone rule changes can affect offsets and DST dates.
• Jet lag recovery time varies by individual and trip conditions.

6. Data maintenance and corrections

Airport and route metadata are maintained in a curated dataset and regenerated into static pages. If you notice an airport code mismatch, route issue, or factual error, contact us with the route URL and correction details so we can review it.

Contact: Contact JetLag Planner