## 3 Materials and Methods
### The Process of Decision-Making Using the AHP Methodology
The previous research [67; 68; 69; 70; 71; 72] lists the most common limitations (shortcomings) of the AHP method:
* The scale used to compare elements in pairs is not large enough, which makes the description of the difference in importance between individual parameters relatively poor. * In a significant number of problems, a large number of comparative pairs occur. * It is very difficult to achieve consistency in a large number of cases. * It is extremely important to structure the problem well, otherwise the criteria and alternatives will not be comparable in a particular model. By reviewing the main advantages and disadvantages of the AHP method, it can be concluded that advantages outweigh the limitations of the method. As the biggest disadvantage, the authors [67; 69; 70; 71] point out an insufficiently large scale for the purpose of comparing parameters during their matching. In general, compared to other MCDM methods, this method has the greatest application in practice, primarily due to its relatively fast and simple implementation. Due to the previously mentioned advantages, most managers choose this method when solving a certain problem. For efficient solving of multi-criteria decision-making problems using the previously explained AHP method, the Expert Choice software (version 2000 2 nd Edition) has been developed. With this software, all steps within the AHP method can be calculated in a simple way. It enables the creation of a hierarchical model structure of the problem and the comparison of all pairs within the hierarchical structure. This software also provides the option of performing and visualizing sensitivity analysis based on a simple interactive way of changing the weights of criteria and alternatives. The Expert Choice software was used in this research. Determining the Optimal Level of Service of the Airport Passenger Terminal for Low-Cost Carriers Using the AHP--Results  
Customer satisfaction with airport services is a key indicator of the efficiency of their operation. In order to achieve customer satisfaction among the target group, questionnaires are often used and distributed among selected respondents. This approach allows for the collection of feedback and suggestions in order to improve or adjust the level of services provided to the target group (passengers). In this paper, the survey questionnaire aims to establish the characteristics of passengers using the services of low-cost carriers, including their needs and desires. In order to better understand passengers and their needs, a survey questionnaire was developed and addressed to respondents (passengers). A survey is a methodological research procedure used to collect qualitative or quantitative data from respondents through questionnaires. This research method can be useful for collecting data on a wide range of topics, including consumer habits, political opinions, social interactions, and other aspects of human behavior, including satisfaction with products or services, which is the case of this survey. At the same time, this survey allows a deeper understanding of passenger needs and contributes to creating a comprehensive view of the characteristics of LCC passengers. The primary objective of this survey is to gain insight into the perception of service quality in an airport passenger terminal from the passenger perspective. It is primarily intended for the users of air transport services, in terms of the (perceived) level of service when moving through the airport passenger terminal. The target group is passengerswho use the services of low-cost carriers regarding the level of service received within the airport passenger terminal, all with the aim of establishing an optimal level of service (LOS) for low-cost carriers (LCCs). The survey results can help to define new spatial-temporal parameters at the airport passenger terminal (space per passenger, maximum waiting time, occupancy of facilities) for the LC airline business model.