The network reliability has become a popular topic and flight network reliability is not an exception. A salient point from related research suggests that network reliability can be one of performance index in the evaluation of the effectiveness of companies or manufacturers. Consequently, flight network reliability is also considered as one of airline's performance indexes. In a flight network, each route can have different states in a range of its capacity therefore such flight network is multistate system with multistate components. In an effort to investigate this disparity, the research presented herein focuses on building a new algorithm to calculate the flight network reliability throughout applying minimal paths (MPs) perspective. This study evaluates system reliability of a flight network for carrying demand d successfully from the origin to the destination under time and the number of stopovers constraints. It is expected that an enhanced finding from proposed algorithm should inform policy makers and company executives in their strategic decision-making with regards to their flight routing and thereby contribute advancement towards sustainability.