Aircraft boarding is one of the critical processes affecting the turnaround time when a plane is at an airport. In this work, the aircraft boarding problem is studied with the aim of designing a boarding strategy that reduces the total boarding time considering the passengers' behavior as well as the underlying grouping relationships among them. Our analysis suggests that some of the strategies proposed in other studies are highly theoretical and do not consider the individual characteristics of the passengers or their grouping inside the plane. This limits their applicability and validity in real operations. We propose a novel boarding strategy that is designed to reduce the total boarding time while, at the same time, aims at guaranteeing an acceptable quality of service.