Currently thousands of flights are delayed and cancelled daily. It is the main teaser of the airlines, because it implements unpredictable additional costs. It is also the main fear of passengers when it comes to taking a flight, since the delay has become routine. This directly affects the reliability of the airline, thus losing customers. The delays of an airline are given by multiple variables. However, we have to face them. A good adjustment of the times is crucial to your greatest success. For this purpose, this project has focused on analyzing the BCN-BRU pair, in order to develop a methodology applicable to other cases. Exactly focused on the time of flight, one of the primordial times to adjust with precision. Throughout this study, a methodology, which has been based on historical data and distribution adjustments, has been developed. It is also based on how much error you are willing to assume in your design times. A fictitious application has been made in which design flight times are assigned and checked against those programmed by the company. The adjustment of the proposed results has been valued, as well as how much is being risked by the company we are evaluating. The methodology gives good results, however, adjusting the flight time is not the only variable to mitigate the delays completely.