This calculator uses the figures from Transport & Environment: a private jet can emit about two tonnes of CO₂ in one hour, while the average person in the EU emits 8.2 tonnes of greenhouse gases in a whole year. Per passenger, they found private jets are 5 to 14 times more polluting than commercial flights, and about 50 times more than a train.
Real emissions depend on the type of jet: a small jet burns far less than a large long-range one, and empty repositioning flights count too. Treat the result as a rough estimate, not an audit. The comparison is with an average EU resident's total emissions, from heating to food, not just their car.
Because public flight data made private jet flights visible, and with them their emissions. That's part of why the ElonJet saga caught on. This calculator isn't about anyone in particular; it's about the aircraft type.