Customer Loyalty in Airline Industry: A Literature Review

: The aviation industry is one of the fastest-growing and highly competitive industries. Managing an airline's passenger loyalty is essential to a competitive business and airline success. The researcher is interested in studying the key factors that affect airline passenger loyalty, which will lead to the strategic planning of airlines in the future. Therefore, the researcher chose to review the literature and previous research in the study to summarize the key factors affecting the loyalty and development of the research model. The study found that seven factors, directly and indirectly, affect airline passenger loyalty: perceived value, perceived service quality, complaint handling, satisfaction, trust, airline image, and commitment. Therefore, airline executives at all levels should focus on managing these seven factors to ensure passenger loyalty and ultimately lead to the success of their airline business.


INTRODUCTION
The aviation industry is one of the industries that generate good profits for the country (Chayomchai, et al., 2021). The airline industry is related to many other industries such as the tourism industry, hotel, and resort industry. Today's aviation business is intensely competitive (Chonsalasin, Jomnonkwao, & Ratanavaraha, 2020;Wang & Chaipoopirutana, 2015). Several previous studies have focused on the greater competitiveness of low-cost airlines (Chayomchai, et  . However, competitive advantage can be gained from other factors such as passenger attitude factor (like consumer satisfaction or passenger loyalty) or airline crew factor. Airline executives need to understand the needs and expectations of passengers or consumers, which in turn influences the planning of services that are more competitive than competitors (Gures, Arslan, & Tun, 2014). The operations of airlines around the world expect good and successful results that lead to sustainable competitiveness. The ability to understand passengers in terms of attitudes, perspectives, and behaviors will affect an airline's bottom line, for example, its focus on passenger loyalty clearly affects its profitability (Ganiyu, 2016;Sakdaar & Chaiwongkeat, 2020). The researcher is interested in exploring the key factors influencing passenger loyalty in the airline. The results of the study are useful for strategic planning of the airline business and also to the academic community in the field of strategic management, marketing, and consumer behavior.

RESEARCH METHODOLOGY
This study used a systematic review of the literature. It is a search for previous literature and research from online sources. The aim of this study will focus on factors related to passenger loyalty in the airline industry. Literature reviews are systematically compiled to summarize factors related to airline customer loyalty, and the results are then used to create a model of the study. The researcher hopes to obtain a model that will be useful to other researchers in the future. The paper indicated that service quality influenced both customer satisfaction and customer loyalty. It showed that customer satisfaction affected customer loyalty. 3 Pi and Huang (2011) Effects of promotion on relationship quality and customer loyalty in the airline industry: The relationship marketing approach It is quantitative research. Sample size was 110 respondents.
Multiple regression analysis was used.
The results found that satisfaction, trust, and commitment significantly influenced customer loyalty. 4 Gures, Arslan, and Tun (2014) Customer expectation, satisfaction and loyalty relationship in Turkish airline industry It is quantitative study. Data were collected from 421 domestic passengers and 400 international passengers.
Structural equation modeling was employed.
The finding showed that passengers' satisfaction positively influenced their loyalty. 5 Hassan and Salem It found that perceived value and trust significantly influenced customer loyalty in airline business. 8 Lembana and Valucy (2018) Could satisfaction on the airline's service quality (AIRQUAL) make lion air's customers trust and become loyal to the airline company? 252 questionnaires were used for this quantitative study and structural equation modeling was performed.
The findings found that (1) service quality significantly affected customer satisfaction but did not affect customer loyalty; (2) customer satisfaction significantly influenced customer loyalty; and (3) customer satisfaction also mediated the relationship between service quality and customer loyalty. 9 Kusumawardani and Aruan (2019) Comparing the effects of service quality and valuefor-money on customer satisfaction, airline image and behavioural intention between full-service and low-cost airlines: Evidence from Indonesia This is quantitative study with 229 respondents. Structural equation modeling was utilized.
The findings indicated that (1) service quality significantly affected customer satisfaction and (2) service quality significantly affected airline image. 10 Lee Customer loyalty drives repeat purchases and airline profitability. Therefore, aviation organizations should focus on the loyalty of the passengers. 12 Namukasa (2013) The influence of airline service quality on passenger satisfaction and loyalty: The case of Uganda airline industry 303 passengers on international flights were sample size in this quantitative study. Multiple regression analysis was performed.
It found that (1) service quality had a significant effect on passenger satisfaction and (2) satisfaction significantly affected passenger loyalty. 13 Sakdaar and Chaiwongkeat, (2020)

Measuring Customer Loyalty for Airline Business
Literature review on customer loyalty in airline business.
It found that passenger loyalty is a key factor of airline success and customer retention. 14 Ganiyu (2016) Perceived service quality and customer loyalty: The mediating effect of passenger satisfaction in the Nigerian airline industry 503 questionnaires were used for statistical analysis in this quantitative research.
Multiple regression analysis was employed.
The findings showed that (1) service quality significantly affected customer satisfaction; (2) service quality significantly affected customer loyalty; and (3) customer satisfaction significantly influenced customer loyalty. 15 Kit (2021) Relationship quality factors on passenger loyalty of the airline industry in Johor, Malaysia Quantitative study with 90 usable questionnaires and PLS-SEM was utilized for statistical analysis.
The results found that (1) perceived service quality significantly affected customer loyalty; Various aspects of service quality, such as staff service and aircraft quality, have a significant effect on the loyalty of airline passengers. 19 Hapsari, Clemes and Dean (2015) The role of customer engagement in enhancing passenger loyalty in Indonesian airline industry: Relationship marketing approach This is quantitative research with sample size equal to 250. Structural equation modeling was performed.
The result showed that perceived value had a significant effect on passenger loyalty.

Customer loyalty
Customer loyalty is a key motivating factor for passengers' continued choice of airline services (Chonsalasin, Jomnonkwao, & Ratanavaraha, 2020). Loyalty is a consumer perspective that relates to organizational or product attitudes that influence consumption, repeat purchases, and telling others (Hassan & Salem, 2022; Yunus, Bojei, & Rashid, 2013). In the past, loyalty was often used to generate repeat purchases, but nowadays, loyalty involves both the moral and behavioral aspects of the consumer, such as repeat purchases and telling others (Pi & Huang, 2011). Customer loyalty is clearly a key success factor for any organization  Lembana and Valucy (2018) in airline industry recommended that focusing on customer loyalty will influence the sustainability of the airline business. This is consistent with Lee, et al. (2018) who indicated that customer loyalty affects corporate bottom line and ultimately leads to sustainable competitiveness.

Perceived value
Perceived value is a very important marketing factor that organizations need to pay attention to especially when it comes to customer satisfaction (Gures, Inan, & Arslan, 2018). Creating value for customers is an essential factor in competitiveness (Hapsari, Clemes & Dean, 2015). The study of Chonsalasin, Jomnonkwao, and Ratanavaraha (2020) in Thailand's airline industry concluded that perceived value significantly influenced passengers' satisfaction and loyalty. The study of Gures, Inan, and Arslan (2018) in Turkish airline industry indicated that perceived value significantly influenced customer loyalty in airline industry. The study of Lee, et al. (2018) in Hong Kong airline business showed that perceived value significantly affected customer satisfaction and perceived service quality. The study of Hapsari, Clemes and Dean (2015) in Indonesian airline industry found that perceived value had a significant effect on passenger loyalty.

Perceived quality
Service organizations need to focus on service quality factors in order to meet customer needs or expectations (Yunus, Bojei, & Rashid, 2013). Aviation business is a service business that emphasizes service quality, which is an important factor in building competitiveness (Chayomchai, et al., 2021). The management who has to formulate corporate policies needs to understand the factors that affect the quality of aviation business services (Chonsalasin, Jomnonkwao, & Ratanavaraha, 2020). If the airline business performs well in service quality, it will result in passenger satisfaction and loyalty (Chayomchai, et al., 2021 (2020) in the airline industry of Thailand revealed that perceived service quality of airline business significantly affected passengers' perceived value and satisfaction. The study of Yunus, Bojei, and Rashid (2013) in Malaysia's low-cost airline business found that service quality influenced customer satisfaction and loyalty. The study of Hassan and Salem (2022) indicated that perceived service quality significantly affected passenger satisfaction and loyalty in the airline industry. The study of Wang and Chaipoopirutana (2015) in Thai Airways airline business pointed out that service quality significantly related with customer satisfaction and loyalty. The study of Namukasa (2013) in airline industry pointed out that service quality had a significant effect on passenger satisfaction. The study of Ganiyu (2016) in Nigerian airline industry showed that service quality significantly affected customer satisfaction and loyalty. The study of Kit (2012) in Malaysian airline business found that perceived service quality significantly affected customer loyalty. The study of Moghadam, Tabriz, Khorshidi, and Menhaj (2014) in airline industry indicated that service quality significantly influenced customer loyalty. The study of Vlachos and Lin (2014) pointed out that various aspects of service quality, such as staff service and aircraft quality, have a significant effect on the loyalty of airline passengers. The study of Lembana and Valucy (2018) in Indonesian airline business indicated that service quality significantly affected customer satisfaction but did not affect customer loyalty. However, they found that customer satisfaction mediated the relationship between service quality and customer loyalty. In addition, the study of Lee, et al. (2018) in Hong Kong airline industry pointed out that perceived service quality significantly affected customer satisfaction.

Satisfaction
The satisfaction is a feeling that is assessed against that person's expectations (Yunus, Bojei, & Rashid, 2013). Having satisfied customers with the services of a business will have a positive effect on the organization's business operations (Gures, Arslan, & Tun, 2014). The study of Chonsalasin, Jomnonkwao, and Ratanavaraha (2020) pointed out that airline passengers' satisfaction significantly affected their loyalty. The study of Yunus, Bojei, and Rashid (2013) in Malaysia's low-cost airline business indicated that passengers' satisfaction influenced their loyalty. The study of Pi and Huang (2011) in Taiwan's airline industry revealed the significant effect of customer satisfaction on customer loyalty. The study of Gures, Arslan, and Tun (2014) who focus on passenger satisfaction and loyalty in Turkish airline industry concluded that passengers' satisfaction positively influenced passengers' loyalty. The study of Wang and Chaipoopirutana (2015) in Thai Airways airline of Thailand indicated that passengers' satisfaction significantly related with customer loyalty. The study of Lembana and Valucy (2018) in Indonesian airline industry found that customer satisfaction significantly influenced customer loyalty. The study of Lee, et al. (2018) in Hong Kong airline business found that customer satisfaction significantly influenced attitudinal loyalty, but did not affect behavioral loyalty. The study of Namukasa (2013) revealed that passenger satisfaction significantly affected passenger loyalty in airline business. The study of Ganiyu (2016) in Nigerian airline business found that customer satisfaction significantly influenced customer loyalty. The study of Moghadam, Tabriz, Khorshidi, and Menhaj (2014) in airline industry found that passenger satisfaction significantly influenced passenger loyalty. The study of Salah and Abou-Shouk (2019) found that passenger satisfaction positively influenced passenger loyalty in airline business. However, the study of Hassan and Salem (2022) indicated that passenger satisfaction did not affect passenger loyalty in the airline business.

Trust
Trust is one of the marketing factors that influence marketing and organizational success (Gures, Inan, & Arslan, 2018). The study of Chonsalasin, Jomnonkwao, and Ratanavaraha (2020) in Thailand's airline industry concluded that passenger trust significantly influenced their loyalty. The study of Pi and Huang (2011) in Taiwan's airline industry revealed the significant effect of passengers' From the literature review and all related research above, the researcher has developed a research model for presentation to the academic community as shown in Figure 1. The researcher focused on the factors affecting airline passenger loyalty. This loyalty is an important factor for the success and competitiveness of the aviation business. The study found that there were seven key factors that directly and indirectly influence airline passenger loyalty: perceived value, perceived service quality, complaint handling, satisfaction, trust, airline image, and commitment. Perceived value not only affects loyalty, but also affects complaint handling, satisfaction, and passenger trust. The perceived quality of service also affects the satisfaction, confidence, and image of the airline. Therefore, in conclusion, the researcher suggested that airline executives should focus on creating value and quality of service excellence for the airline's passengers, which