The real odds
Per flight, mostly US airlines, latest full-year figures. Dots sit on a log scale, so each tick is ten times rarer than the one before it. Rows marked rough are built from two public figures, with the math in the source line.
What 1 in 80 million means
It's the odds that you, holding a boarding pass, die on that flight. MIT counts every death on every airline flight in the safest countries over five years and divides by every passenger who boarded. A crash that kills a fifth of the people on board counts as a fifth of a death per passenger, so partial crashes are already in the number. Nothing about it is lifetime: it's one roll per boarding. The app rolls a major accident first, then how bad it is, then whether you're among the people who don't make it. The branches multiply out to the same 1 in 80 million.
Your plane
Which plane you get follows real US flight counts (Cirium, April 2025) and the route length each type usually flies. Hull-loss rates are Boeing's worldwide figures per million flights since each type entered service. The app uses them only as relative weights on the major-accident roll, capped at half to double, because one accident in a small fleet swings a number and the differences between modern types are mostly noise.
Weather
Each flight rolls the weather at both airports from NOAA's monthly averages (days with rain, snow, thunder and the usual wind) for the current month, with storms leaning afternoon and fog leaning morning. Rough weather multiplies the odds below; clear days divide them. The averages are then normalized across a year of random flights so every event still lands on its published rate. BTS puts weather behind about 30% of all US delays.
How this works
Everything in the odds list is rolled independently on every flight at its real rate. The everyday stuff (security lines, gate changes, babies, dogs, drinks) and the rare weird moments are added for color. Each one is something that really happens on US flights, but its rate is a guess, not a published number. Flight times come from the real distance between the airports, and every clock shows local time.
Use this to retrain your gut over a few sessions. If you catch yourself needing to run it before every real flight, take a break from it, since checking for reassurance can keep a fear going.