Discrete-event model: identify critical processes

You have been asked to develop a mathematical model to optimize the flow of passengers in an airport from the time they arrive until they board an airplane. This summer, the airport experienced major delays and bottlenecks due to high demand, and the management wants to ensure these problems don't repeat next year.

You have decided to build a discrete-event model to propose solutions. You'll first identify the critical steps that affect the passenger flow speed, which need to be included in your model. There are endless situations that the passenger can experience, but you need to identify the critical ones that may affect waiting times and cause delays.