Abstract-Continuous Descent Operations with ControlledTimes of Arrival (CTA) at one or several metering fixes could enable environmentally friendly procedures without compromising capacity. This type of flight operation requires advanced on-board systems not only able to compute a plan satisfying Required Times of Arrival (RTAs), but also to safely and efficiently guide the aircraft during the execution of the descent such that RTAs are accurately accomplished. The primary aim of this paper is to compare the performance (in terms of environmental impact mitigation and ability to fulfill operational constraints) of four guidance strategies: tactical, strategic, hybrid and Model Predictive Control (MPC). A high fidelity flight simulator has been configured, and several descents to Barcelona-El Prat airport (Spain) have been simulated in presence of weather forecast and aircraft performance modeling errors. Results show that MPC is the most robust in terms of energy and time deviation, providing at the same time excellent environmental impact mitigation.