market size – the number of passengers (usually expressed per day) traveling on a True Origin and Destination
onboards – the actual passenger count on a particular segment (a specific flight)
load factor – defined as RPM/ASM; a measure of capacity utilization, expressed in a percentage such as 85%;
In many cases, people mix load factor with seat factor (see definition below). In fact, those two metrics are only the same in each flight sector. When multiple sectors are aggregated, the load factor gives more weight to long-haul sectors because it includes a distance component.
seat factor– defined as the number of passengers carried / seats available.
pax – short for “passenger”
seats – available passenger capacity on a specific plane, or aggregate passenger capacity in a market over a given time period. Seats is sometimes used as a benchmark for determining if a market’s passenger estimate is reasonable. For example, if seats in a market are 6000, and the passenger estimate is 5000, then the load factor (LF) is 83.3% which is in the reasonable range.
penetration – a measure (usually expressed as a percentage) of how well a data source (such as agency settlement data) captures the total amount of traffic in a market