Delays in the check-in system at an airport vary with times of the day, day of the week, and types of check-in modes chosen by the passengers. Extensive data collection of the check-in system can be used to build a simulation that helps predict these delays. This paper explains the data collection process, simulation modeling, and scenario analysis for the check-in procedure at the Buffalo Niagara International Airport. Results from this study can be linked to other processes (security checkpoint and parking) in order to obtain information on a passenger’s experience at the airport. The goal of this study is to identify delays and create scenarios that will improve the efficiency.