A method and apparatus for mounting lines in an aircraft. A line mounting system for the aircraft comprises support structures and spacers. The support structures are configured to slide into positions relative to attachment structures in the aircraft and connect to the attachment structures in the positions. The spacers are associated with the support structures. A number of lines is configured to be connected to the spacers. The number of lines is held in a desired configuration in the aircraft when the support structures are secured to the attachment structures.