Aircraft boarding has a direct influence on the operational cost of an airline. Therefore it has become imperative for the airline industry to find better boarding methods that minimize the boarding time thereby reducing the turn-around time of flights. Agent-Based Simulations (ABS) offer a way to investigate optimal boarding strategies. Complex interactions between multiple passengers during the process of boarding can be modeled using ABS to discover the factors causing most delays and to compare the performance of suggested new models. This study performs a critical review of 12 studies that investigate the aircraft boarding problem using ABS to compare their results. The study classifies the reviewed papers into three groups based on the objective of the investigation: (1) studies that evaluate the efficiency of various boarding strategies, (2) studies that evaluate new methods for aircraft boarding, and lastly, (3) studies that evaluate the impact of COVID-19 restrictions on aircraft boarding.