This report seeks to discuss about Breadth-first search (BFS) for flight scheduling. BFS starts at the first node of a graph, and explores the neighbouring nodes before moving on to the next level of neighbours, finding every other neighbour that is at the distance k before exploring any vertices that are distance k+1. There is no order involved when we explore the neighbouring nodes. Each node can only be visited EXACTLY once, and every edge, twice, in a forward direction as it is visiting neighbouring nodes, and once backwards, when it is backtracking after it’s done searching through all the neighbouring nodes. A queue system, which utilises the First-Come First-Serve implementation, is used to store the neighbouring vertices which will be visited after the current vertex. Every instance of visiting a vertex, it will be marked as “visited”, such that it will not be put in the queue and be visited again. BFS will be done till all vertices in the graph has been visited, that is, when the queue becomes empty.