In this paper, I empirically identify a new source of price discrimination utilized by airlines, namely, price discrimination based on the day of the week a ticket is purchased. Using unique transaction data, I compare tickets that are identical in every aspect except day of the week purchased (that is, traveling on the same date on the same route on the same airline with the same restrictions on flights with the same load factors and purchased the same number of days in advance), and find that airfares are cheapest when bought on the weekend. The size of this weekend purchase effect varies with distribution channel (online or offline) and how far in advance of departure the ticket is purchased. For transactions occurring more than two weeks before the departure date, offline weekend purchases are 3% cheaper than those made on weekdays, but online purchase prices do not differ significantly throughout the week. Conversely, in the final two weeks before departure, weekend purchases are 4% less expensive online but not significantly cheaper offline. These findings are consistent with price discrimination between high-elasticity leisure customers and low-elasticity business customers. If airlines believe that weekend purchasers are more likely to be price-elastic leisure travelers, then they may offer lower prices or make deals more transparent on the weekend. This conjecture is supported by the finding that the weekend purchase effect is generally larger on routes with a mixture of both business and leisure customers than on routes primarily traveled by leisure customers because price discrimination is both possible and effective on these heterogeneous routes.

Although the airline industry has drastically changed since its deregulation in 1978, publically available sources of data have remained nearly the same. In the U.S., most researchers and decision-makers rely on government data that contains highly aggregated price information (e.g., average quarterly prices). However, aggregate data can hide important market behavior. With the emergence of online distribution channels, there is a new opportunity to model air travel demand using detailed price information. This dissertation uses online prices and seat maps to build a dataset of daily prices and bookings at the flight-level. Several research contributions are made, all related to leveraging online data to better understand airline pricing and product strategies, and how these strategies impact customers, as well as the industry in general. One major contribution is the finding that the recent product debundling trend in the U.S. airline industry has diluted revenues to the U.S. Airport and Airways Trust Fund by at least five percent. Additionally, several new behavioral insights are found for one debundling trend that has been widely adopted by U.S. airlines: seat reservation fees. Customers are found to be between 2 and 3.3 times more likely to purchase premium coach seats (with extra legroom and early boarding privileges) when there are no regular coach window or aisle seats that can be reserved for free, suggesting that the ability of airlines to charge seat fees is strongly tied to load factors. Model results are used to explore optimal seat fees and find that an optimal static fee could increase revenues by 8 percent, whereas optimal dynamic fees could increase revenues by 10.2 percent. Another major contribution is in modeling daily bookings and estimating price elasticities using ordinary least squares (OLS) regression without correcting for price endogeneity and two-stage least squares (2SLS) regression, which corrects for endogeneity. Results highlight the importance of correcting for price endogeneity (which is not often done in air travel applications). In particular, models that do not correct for endogeneity find inelastic demand estimates whereas models that do correct for endogeneity find elastic demand estimates. This is important, as pricing recommendations differ for inelastic and elastic models. A set of instrumental variables are found to pass validity tests and can be used to correct for price endogeneity in future models of daily flight-level demand.

L’objectif de cette thèse est d’analyser les contributions de Clément Colson à la science économique dans le but de mieux connaître sa pensée, de mieux connaître l’École libérale française au début du XXème siècle, d’étudier l’influence qu’a pu avoir cet auteur sur ses principaux élèves, Divisia, Roy et Rueff, et d’évaluer l’actualité de certaines de ses recommandations.Le premier chapitre montre quels sont les apports théoriques de Colson à la science économique.Pour ses élèves, son principal apport serait la théorie de la détermination conjointe du salaire et du taux d’intérêt. Nous montrerons que cette théorie est proche de la règle de gestion optimale en microéconomie attribuée à Clark ; nous verrons alors que l’on peut parler de découverte multiple.Colson est également intéressant au point de vue de la méthode utilisée. Nous verrons alors qu’il utilise les statistiques et les mathématiques dans ses développements : il est à l’origine d’une évaluation pionnière du revenu de la France, son enseignement impulse le calcul économique, il peut être considéré comme un précurseur de l’économétrie en France. Le deuxième chapitre montre que Colson développe la méthode de tarification des voies de communication exploitées en monopole de Jules Dupuit en proposant des moyens pratiques de révélation des préférences. Nous verrons également que cette théorie est reprise de nos jours avec le Yield Management et par les compagnies aériennes à bas coûts. Le troisième chapitre a pour but de voir comment Colson prend en compte la question sociale. Nous verrons qu’il défend une intervention de l’État plus importante que d’autres économistes libéraux afin d’éviter que les ouvriers ne se tournent vers le socialisme. Le quatrième chapitre étudie l’intervention de l’État préconisée par Colson dans le domaine des chemins de fer. Nous verrons que dans ce domaine où l’État est très présent, l’auteur souhaite le limiter. Il préfère ainsi la concession à la régie et souhaite la construction de nouvelles lignes uniquement si elles sont rentables. Nous verrons qu’à nouveau, la crainte du socialisme n’est pas étrangère à ses positions. Sur chacun des thèmes, nous verrons que Colson accorde à la pratique une place importante. Au niveau théorique tout part de l’observation et se termine par l’observation, au niveau pratique il est marqué par les préoccupations de son époque. / The object of this dissertation is to analyse the contributions of Clément Colson to the economics in order to be better acquainted with his thought, with the French Liberal School at the beginning of the 20th century, to see the influence he had on his main students, Divisia, Roy and Rueff, and to evaluate the actuality of his recomandations. The first chapter develops the Colson’s theoretical contributions.For his students, his main contribution would be the theory of the joint setting of wage and of the interest rate. We will explain this theory is close to the optimal management rule in microeconomics attributed to Clark; we will see we can speak then about multiple discovery.Colson is interesting too from the point of view of the method used. We will see he uses statistics and mathematics in his developments: he makes one of the first assesments of the French income, his lectures develop economics calculus, he can be seen as a precursor of econometrics in France. The second chapter shows that Colson develops the Jules Dupuit pricing method for means of communications exploited by a monopoly by proposing practical way of preferences revelation. We will show too that this theory is used nowadays with the Yield Management and by airline lowcost companies.The third chapter has for purpose to see how Colson takes into account the social question. We will see he argues for a more important State intervention than other liberal economists in order to avoid workers to turn to socialism. The fourth chapter is devoted to the State intervention recommended by Colson in the field of railways. We will see that in this field in which the State is very present, the author wishes to limit it. So he prefers the concession to the public exploitation and wishes construction of new railway lines just if they are profitable. We will see again that the fear of socialism is not stranger to his positions. On each theme, we will see that Colson gives an important place to the practice. At the theoretical level all starts and finishes with the observation, at the practice level he is influenced by the preoccupations of his time.