The competition between high-speed rail (HSR) and air transport has emerged as a significant topic of interest in transportation research. Increasingly, countries around the world are investing in HSR to reduce travel times between major commercial regions, thereby facilitating user mobility and enhancing cultural, social, and economic interconnections. Numerous studies have highlighted that the introduction of HSR into the market could significantly impact the aviation sector, particularly on short-to medium-distance routes where HSR presents a formidable competitor to air transport. This study aims to identify the various methodologies employed in analyzing HSR-air transport competition, categorizing them into macro categories; to distinguish between studies that analyze real-world case studies and those that do not. To this end, we conducted an exhaustive review of existing scientific publications on HSR-air transport competition. Using the Bibliometrix R tool, we analyzed documents retrieved from the Web of Science (WoS) database between 2004 and 2023. The study examined published sources and their most significant contributions, highlighting the key authors, institutions, and countries that have made substantial contributions to this field. Furthermore, a keyword analysis was conducted to identify the most frequently used terms in the reviewed works, culminating in the creation of a “word cloud” that visually represents these keywords. This comprehensive review provides a valuable resource for understanding the current state of research on HSR and air transport competition and identifies areas for future research focus.