In U.S. railroad practice, a flying junction is a track configuration in which merging or crossing railroad lines provide track connections with each other without requiring trains to cross over in front of opposing traffic.

As its name implies, a flying junction accomplishes this separation by having individual tracks rise and /or fall to pass over or under other tracks. Simple flying junctions may simply have a single track pass over the mainline to avoid conflict, while complex flying junctions may have an elaborate infrastructure to allow multiple routings among a variety of tracks without trains coming into conflict.

The opposite of a flying junction is a level junction, where all tracks cross at grade and routings must be controlled by signals and an interlocking plant.