Standard Definitions

Below are the standard definitions used in this blog.


Available Seat Miles (ASMs) - Multiplying the number of seats times the distance flown. Example, a CRJ200 (50 seats) operating DEN-OKC (495 miles) would produce 24,750 ASMs (50 seats x 495 miles = 24,750 ASMs)

Revenue Passenger Miles (RPMs) - The number of miles flown by paying passengers (including award tickets). Example, 45 passengers flying from DEN-OKC (495 miles) would produce 22,275 RPMs (45 passenger x 495 miles = 22,275 RPMs). Note, a passenger produces RPMs on each leg they fly, regardless of their O&D.

Segment Yield - The summation of leg ticket revenue divided by total RPMs. For example, DEN-OKC  flight with 45 passengers with an average segment fare of $120 would produce a segment yield of 24.2 cents. (45 passengers x 120 average fare / 22,275 RPMs = 24.2 cents per revenue passenger mile)

Revenue per Available Seat Mile (ASMs)  - Leg prorated ticket revenue per available seat mile. This does not include ancillary services (bag fees, change fees, cargo, other revenue streams). For example, a DEN-OKC operated by a CRJ200 (50 seats) with 45 passengers with an average segment fare of $120 would produce a RASM of 21.8 cents. (45 passengers x $120 average segment fare / 24,750 ASMs = 21.8 cents revenue per available seat mile)

Cost per Available Seat Mile (CASM )- Fully allocated flight costs, including direct and indirect costs divided by ASMs

Average Stage Length (ASL) - Total miles flown (by aircraft) divided by the number of completed trips.

Segment Average Fare -  Total prorated leg revenue divided by revenue passengers on the flight.

Nonstop Passenger - A passenger-only flying between two cities without stopping or connecting. 

Connecting Passenger - A passenger flying more than one flight leg to get to their final destination. A connecting passenger will be counted on each leg they fly on.

O&D Passenger - A passenger flying between two markets, regardless on the number of stops. For example, a passenger flight from OKC-DEN-SFO would be considered a single O&D passenger flying the OKC-SFO O&D market.

O&D Fare - Total ticket revenue for a market divided by O&D passengers

O&D Market  - The two cities originates and ultimately travels to. For example, a passenger flight from OKC-DEN-SFO would be considered a single O&D passenger flying the OKC-SFO O&D market.

Ticket Revenue - Revenue charged by the airline directly associated with the ticket. This revenue is subject to the government's 7.5% excise tax. Customer usage or ticketing fees are not included in this revenue figure.

Ancillary Revenue - Revenue charged by airlines not captured under ticket revenue. Passenger usage, baggage fees, and change fees are the most common examples of these types of fees. 

This page will be updated with other definitions as terms are used in future posts.

This page was last updated: 10/7/2019

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