## 7 Conclusions  
This paper proposes a methodology for planning/optimizing the capacity of airport terminal facilities at passenger terminals where there is a visible trend of change in the shares of airline business models, based on forecasts of traffic demand and the shares of airline business models. In this research, forecasting of traffic demand and the shares of airline business models was made for a case-study airport, i.e., Pula Airport. The forecasting techniques of Python and MS Excel were used. Based on traffic demand forecasts and shares of airline business models, guidelines were proposed for future planning of airport terminal facilities. An example of an adjusted airport terminal facilities' layout at Pula Airport passenger terminal is demonstrated using AutoCAD, according to forecasted traffic demand and the shares of airline business models. The importance of the study lies in the fact that the structure of the airline business models at an airport is changing, where low-cost carriers become more dominant over traditional or charter business models. Hence, airports need to adjust to these changes accordingly to maintain profitability and keep passenger satisfaction at an acceptable level of service. The method of forecasting the traffic demand and shares of airline business models at an airport provides an insight into the future conditions and gives the opportunity to adjust airport terminal facilities at an airport passenger terminal to future scenarios. One example is provided for an adjustment of the check-in area of the airport passenger terminal at Pula Airport. A key limitation of the research that can be identified lies in the fact that forecasts are not entirely accurate and should always be taken with a degree of caution. Although they are based on the analysis of historical data and various factors, the future is always subject to changes that cannot be fully predicted. This includes unforeseen events such as economic crises, pandemics like the recent COVID-19, political changes, technological innovations, or natural disasters, which can significantly impact the market. Therefore, forecasts are useful as guidelines, but there is always a certain degree of uncertainty. It is also important to mention potential external factors such as possible regulatory changes, airline competition, or economic changes that may affect this trend (of LCC growth). For example, when considering the regulatory aspect, it is important to consider the possibility of introducing stricter regulations that may increase costs for low-cost carriers, which could potentially lead to higher ticket prices and reduced competitiveness. Also, if regulations regarding safety and health become stricter (such as stronger requirements for baggage screening, health care, or testing), this could increase operating costs for LCCs, which could negatively affect their low ticket prices (and reduce competitiveness). It is known that LCCs mostly operate on the principle of low prices and high flight frequencies, and increased competition, especially from full-service carriers introducing low-cost options, may reduce the market share of LCCs, as competitors may offer similar services with better connectivity or additional services. Other factors, such as economic recessions and their impact on the LCC growth trend, can also be taken into account. In fact, low-cost carriers usually profit in economic crises because passengers are looking to reduce the cost of travel. In times of recession, low-cost options become more attractive to the general public. By comparison, during periods of economic growth, demand for travel increases, but competition in the sector can become more intense; thus, LCCs face the challenge of maintaining low prices while increasing passenger numbers. In addition to the above, various other factors, such as geopolitical factors or technological innovations, can be taken into account. Geopolitical uncertainty may increase travel uncertainty, which could impact LCCs and reduce flight demand.