Receptor

This section will present the measures applied for ensuring that the sample employed for this survey is representative of the population that the results of the survey will be referring to. Moreover, the reasons why Athens International Airport has been selected as an appropriate airport for this survey and the sample requirements set in order to be able to meet the objectives from the results obtained will also be presented.

3.4.8.1 Sample Methodology

The population in this research is defined as: “All passengers that are aware of what airline alliances are and have travelled with an airline belonging to one of the three global alliances in the last two weeks”. The “last two weeks” criterion includes passengers who have used recently one of the airlines under investigation and therefore are able to evaluate their quality of service for the elements considered.

3.4.8.2 Sample Size

One of the most critical decisions in every survey is to define a sample size that will be sufficient to validate the results of the study and to enable the generalisation of the

conclusions drawn from the survey’s sample to the whole population that the sample aims to represent. A number of questions can be raised at this moment regarding the definition of the whole population. Since the survey will be carried out at a particular airport and the targeted population are the alliance passengers, then the timeframe within which the targeted alliance passengers are flying to and from the airport should also be defined.

Considering the large number of airlines under investigation, a percentage that is considered as representative of one flight for each airline would be considered as providing valid results. By using the typical 10% or 20% sample of the whole population and considering an average aircraft size with 180 seats, then 18 to 36 responses from each airline would be considered as a representative sample.

Both Matear (1991) for a similar study for sea ferry passengers and Mason (1995) for a similar study for business air travellers have operated a sample size target of 10% of the population considered. Therefore, the sample size target by airline will be equal to 10% of the total daily passengers travelling from Athens International Airport with the respective airline. In Appendix K, all flights from Athens Inetranational Airport for all the airlines belonging to one of the three alliances are presented, together with their respective aircraft types and seating capacity and their assumed daily passengers (applying a 70% load factor). By applying the 10% sample size factor to the total daily passengers by airline, the required sample size by airline is calculated.

3.4.8.3 Athens International Airport

Athens International Airport was selected as an appropriate airport to carry out the airline passenger survey for four main reasons:

1. It is one of the few major European airports in terms of annual passenger traffic for which neither of its based airlines (Olympic Airways and Aegean Airlines) is a member of any of the three airline strategic alliances, and therefore this research will not be biased towards any of the alliances;

2. It has services offered by airlines participating in all three strategic alliances and therefore permits the analysis of all three major strategic alliances;

3. It has received awards as a high quality airport, ensuring that the results of the airline passenger survey are not negatively influenced by the airport’s poor services (e.g. baggage reclaim times or delays generated by the airport’s services);

4. Athens is a major international city destination and therefore an appropriate case study airport to identify the extent to which airlines not having direct services to Athens Airport use other members of the same alliance to transport their customers.

The airlines that operated to Athens International Airport during the time that the survey took place from each global alliance were:

Star Alliance: Austrian Airlines; BMI (code-share); LOT; Lufthansa; SAS, Singapore;

Spanair (code-share), Swiss; TAP (code-share); Thai.

Oneworld: British Airways; Iberia; Qantas (code-share).

SkyTeam: Aeroflot; Air France; Alitalia; CSA; Delta Airlines; KLM.

At the time (May-June 2006) of the survey:

- Star Alliance had 17 members, 10 of whom were offering services to Athens (3 on code-share agreements: BMI; Spanair and TAP), resulting in a 59% airline representation in terms of alliance membership;

- Oneworld had 8 members, 3 of whom were offering services to Athens (Qantas as a code-share), resulting in a 38% representation in terms of alliance membership;

- SkyTeam had 10 members, 6 of whom were offering services to Athens, resulting in a 60% representation in terms of alliance membership.

Therefore all three alliances have a significant representation in terms of number of airlines operating to the case study airport, although Oneworld is the least well represented of the three alliances.

3.4.8.4 Ensuring Fairness in Airline Representation

In order to obtain valid results a similar number of respondents for each airline participating in the survey is required. As has already been identified in the sample size

determination, 18 to 36 respondents from each airline have been identified as an adequate number of responses to ensure validity for the results. This criterion can be planned to be satisfied for the airline alliance members operating to Athens International Airport by carrying out the survey in their dedicated areas. The number of respondents for airline alliance members not operating to Athens Airport cannot be planned since this group of respondents will be identified by chance by asking the respondents whether they have used any of these airlines for either the first leg of their journey or for another flight in the last two weeks.