Joachim Grammig, Reinhard Hujer and Michael Scheidler, "Discrete Choice
Management in Airline Network Management",  Journal of Applied
Econometrics, Vol. 20, No. 4, 2005, pp. 467-486.

Data used for estimation were provided by Austrian Airlines. The rows in
the data contain information about consolidated itineraries from four
major CRSs, Amadeus, Galileo, Sabre, and Worldspan, covering the period
of October 1 to October 31, 1996. We focus  on a subset of German
domestic Origin and Destination (O&D) markets. A second market selection
criterion required that Lufthansa (carrier code LH) and Deutsche British
Airways (carrier code DI) offered nonstop or connecting flights at least
twice a day. In order to  reduce the computational burden, we restricted
our attention to Monday departures. The data were aggregated by flight
numbers such that they represent a standard weekday. The selection
criteria resulted in 10 O&D markets with 229 itineraries attracting
non-zero passenger demand. Descriptive statistics on the resulting data
can be found in the paper.

Each of the 229 itineraries are represented in one record in the ASCII file
(in DOS format) estdat.txt, which is zipped in the file ghs-data.zip.  The
itineraries are sorted per O&D market, the columns are described as follows:

Column 1 - number of the market, counting from 1 to 10
Column 2 - number of the alternatives per O&D market
Column 3 - number of passengers per alternative
Column 4 - nonstop flight (=1), or connection (=0)
Column 5 - online connection (=1) means all flights of the itinerary
       	   are operated by the same airline
Column 6 - elapsed time of the alternative
Column 7 - elapsed time for nonstop flights, 0 for connect flights
Column 8 - departure time of the flight, in minutes from midnight
Column 9 - Deutsche BA online flight
Column 10 - Lufthansa online flight
Columns 11-16 - Used to identifiy time-of-day "nests" in alternative
	      	specifications of the nested logit model.