## 1 Introduction  
There are three basic airline business models, namely the traditional or \"network\" (Full Service Carrier--FSC or Full Service Network Carrier--FSNC), low-cost (Low-Cost Carrier--LCC), and charter (Charter Carrier--CC) business models. Each of these business models has its own features and strategies to attract passengers. The business model of low-cost carriers was based on different principles than traditional full-service network carriers, with an emphasis on reducing costs to enable the lowest prices in target markets.  
The evolution of the low-cost model in Europe took at least a decade longer than in the USA, as the first low-cost carriers only emerged after the completion of a liberalization process that took place in several stages, starting in the late 1980s and lasting until the mid-1990s [1]. The low-cost business model typically uses newer, more homogeneous, mid-sized fleets, dense seating configurations, point-to-point flights from smaller, less congested airports, direct ticket sales via the internet (without intermediaries or agencies), basic transportation services, etc. [2, 3, 4].  
According to data in 2023, low-cost carriers account for a significant share of the air transport market, often ranging from 30% to 35% of the global market. This market segmentation continues to grow, especially after the recovery from the COVID-19 pandemic.  
The low-cost carriers' market is expected to grow to more than USD 254 billion by 2027. These estimates have held up despite the challenges caused by the pandemic, and many analysts expect further growth due to the recovery in passenger traffic and changes in demand for air travel [5]. Recent data also show that the low-cost carriers market continues to grow strongly, especially after the pandemic. The global LCC market is forecasted to reach USD 440.5 billion by 2030, with a compound annual growth rate (CAGR) of 15.2% from 2023 to 2030. The growth is primarily driven by technological advances, changing passenger preferences towards more affordable options, and the expansion of secondary airports that reduce carriers' operating costs [6].  
The low-cost terminal (LCT) design concept is based on cost reduction with a simultaneous emphasis on terminal operational efficiency. Key elements include reducing the size and space of the terminal, providing basic services, and ensuring an adequate quality of service that meets the needs of airlines and passengers. The provision of basic airport terminal facilities depends on the type of airport operations, the structure of the fleet, and the volume of passenger traffic [7; 8]. A significant number of LCTs were built as a result of the growth of the share of LCCs and the need to adapt passenger terminals to their simplified requirements.  
In this research, forecasting of traffic demand and the shares of airline business models were made. 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 layout adjustment of airport terminal facilities at Pula Airport passenger terminal is presented using AutoCAD, according to forecasted traffic demand and the shares of airline business models.