is a manager at Lufthansa German Airlines in the network management IT department. He joined Lufthansa in 1995 and is now responsible for the revenue management and reporting systems. Stefan holds a PhD in Computer Science from the University of Dortmund, Germany. He is recognised as an expert in forecasting and revenue management methods and has given presentations at several AGIFORS conferences

Correspondence: Stefan Pölt, Lufthansa German Airlines, Network Management IT, FRA ID/P, 60546 Frankfurt, Germany Tel: +49 69 696 5683; E-mail: stefan.poelt@dlh.de

Revised 15 April 2004.

Abstract

Over the last few years more and more airlines have moved from leg to origin and destination (O&D) control. O&D control better reflects the value of a booking request in the availability calculation. O&D availability is usually calculated for each itinerary, booking class, point of sale and departure date separately. This paper tackles the question of how to aggregate O&D availability, eg for management reports. Management reports present data on a high aggregation level such as country to country and departure month. Since many different O&Ds compete for the same physical seat on a flight, a simple summation of O&D availability leads to double counting. This paper presents two different mathematical models which avoid and factor out this double counting.