Efficient fuel management in airlines is of particular importance due to the high share of fuel costs in flight operations.In competitive aviation markets, optimal fuel management provides significant advantages. Variable fuel prices and supply constraints may force aircraft to carry extra fuel, reducing procurement costs but increasing consumption. This study presents a linear programming model to determine optimal fuel loading in an airline flight network, considering aircraft technical and operational constraints, variations in fuel prices across airports, and flight conditions. Unlike conventional methods that typically operate segment-by-segment with a fixed fuel consumption factor, the proposed model represents fuel consumption as a function of flight distance, cruising altitude, and meteorological conditions, while also accounting for aircraft weight effects. To evaluate the model, real operational data from a Brazilian airline network comprising 12 flight segments were used. Results show that despite a slight increase in fuel consumption, the approach leads to a significantly reduction in total fuel procurement costs—equivalent to over USD 2.3 million in annual savings for a 10-aircraft fleet. The analysis indicates that maximum fuel loading occurs at airports with lower fuel prices, while at high-price airports it is limited to the legal minimum. These findings demonstrate that the proposed model can reduce operational costs and improve fuel efficiency in airline operations.A discussion of the environmental impact of this process is also presented in the article.