Active Flights · Blog

Blog

Clear explainers on aviation and space, SSIM and schedule data, and the industry — from the team behind Active Flights.

Articles

Three separate rings, sized and labelled with the member counts of Star Alliance, SkyTeam and oneworld, on an Active Flights blog card.

Airline alliances explained: Star Alliance, oneworld and SkyTeam

Airline alliances explained: how Star Alliance, oneworld and SkyTeam began, who belongs, what they give travellers, and how they differ from codeshares.

A short bar for revenue up 21% beside a much taller bar for fuel costs up 69%, captioned Delta's third quarter, on an Active Flights blog card.

Airline earnings Q3 2026: record revenue, fuel takes the profit

Airline earnings for Q3 2026: Delta, United and Southwest stayed profitable, American and Alaska lost money. Record revenue at four of them — and fuel up over 60%.

Thin arcs fanning out from one North American point to a scatter of smaller European cities, with '8 of 10' highlighted for United's new cities no other US airline flies to, on an Active Flights blog card.

Airline route growth 2027: where the new flights are going

Airline route growth for 2027: US airlines head for Europe's smaller cities, Air Canada adds five cities, Riyadh Air scales up and Ryanair shifts to Italy.

A row of ten slot tiles with eight lit and two dark beneath a large 80/20, on an Active Flights blog card.

Use It or Lose It: The 80/20 Airport Slot Rule, Explained

The 80/20 slot rule: fly a slot series 80% of the time or lose it. Where it applies, what COVID changed, ghost flights, and where the rule stands now.

Departures on each weekday of an illustrative route drawn as bars, Friday highlighted, on an Active Flights blog card.

Why counting flights and seats from SSIM is harder than it looks

Weekly frequencies and seats are the first figures anyone wants from a schedule — and the ones most often wrong. The traps behind the numbers, and why they matter.

A map of city dots joined by faint dashed candidate routes, with one route drawn bright and an aircraft on it, on an Active Flights blog card.

How Airlines Decide Which Routes to Fly

How airlines decide which routes to fly: demand, rivals, the right aircraft, airport slots, hub connections, seasons, and whether the route makes money.

A validation checklist with one item flagged, on an Active Flights blog card.

Why SSIM files fail quietly — and why validation matters

An SSIM schedule can be wrong without ever raising an error. What goes wrong in real files, what it costs downstream, and why validation has to come first.

The three-letter code LHR and the four-letter code EGLL side by side, both pointing to London Heathrow, on an Active Flights blog card.

IATA vs ICAO airport codes: why Heathrow is LHR and EGLL

IATA vs ICAO airport codes explained: why airports have a three-letter and a four-letter code, who assigns each, where they're used, and why LAX has an X.

Flight XX 123 drawn twice: variation 01 as two legs through a middle station, variation 02 as one non-stop leg, on an Active Flights blog card.

Itinerary variation and leg sequence in SSIM

How SSIM names a flight leg: airline, flight number, itinerary variation and leg sequence. How variations are numbered, the overflow byte, and multi-leg dates.

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