COVID-19 arrived in the world suddenly and unexpectedly. It caused major disruptions at economical, operational, and other levels. In the case of flight traffic, the operations were reduced to 10% of their original levels. The question after COVID-19 is how to restart the operations and how to keep the balance between safety and capacity. In this paper, we present an analysis using simulation ... [Show full abstract] techniques for understanding the impact in a security area of an important airport in Latin America; the airport of Mexico City. The results allow illustrating the potential congestion given by the implemented covid-19 restriction, even when the traffic recovers only by 25% of the pre-covid-19 traffic. The congestion can be mitigated by applying some layout changes (snake queue vs parallel queue) and when more capacity is added to the system (extra security line). The results will raise situational awareness for airport stakeholders when implementing the actions suggested by different international institutions like WHO, IATA or ICAO.