In this paper a new concept aimed at better dealing with delays caused by regulations is presented. Inspired in future 4D trajectories, where a time constraint can be applied at each way-point, it is proposed to spread the total delay imposed by a regulation over the trajectory that goes from the departing airport to the regulated airspace. Given a nominal cruise speed, there exist a set of possible lower speeds that allow a longer flight (and then, a cumulative flight delay) with the same or less fuel consumption if compared with the nominal situation. In this way, the aircraft that has been delayed can consider to take-off on time and loose this time by flying slower and requiring the same or less fuel than initially planed. Besides the positive environmental impact, the airliner can bet that finally the regulation at the congested airspace may be not applied and being the departure on time, the delay can be absorbed more easily in flight with a minimal or null fuel consumption increase. Finally, this concept is applied to some example flights.