direct flight – a non-stop or a one-stop flight. It is also a marketing gimmick – “the biggest lie in airline marketing” – because most people think it is a non-stop flight. 

non-stop – a flight that consists of a single leg 

one-stop – a flight that lands at a city and then continues to another city using the same flight number. Passengers might even be permitted to stay on the plane. 

one way  – a ticket that does not include a return trip to the point of origin airport 

round trip – a ticket where the passenger returns to the point of origin 

trip break – a destination where the customer goes for a purpose other than catching a connecting flight. Trip breaks can be for leisure, business, or VFR (visiting friends & relatives). Because we do not know the passenger’s intent, trip breaks can be identified mathematically by ground time, a highly circuitous (out-of-the-way) routing, and other methods such as return to a previous airport. The destination of the trip break is the True Destination of the Trip / True O&D. 

local traffic – traffic that has the same True O&D as the segment O&D 

connect points – the airports on an itinerary between the True Origin and the True Destination.

double connect – a trip containing a combination of three and only three direct flights. 

minimum connect time – aka “MCT” – the amount of time needed, at a particular airport, to make a connection. Can vary by airline and international vs domestic, online versus interline, etc. 

single connect – a trip containing a combination of two and only two direct flights. 

interline ticket – a ticket that involves two or more marketing airlines.

online ticket – a ticket that has all coupons serviced by a single marketing airline.