LAX to Sleepy Hollow
6 connections
LAX
Lost
You can see advertisments for Oceanic Airlines in a LAX terminal, which is the airline of the plane that crashed on Lost
Veronica Mars
In an episode of Veronica Mars, Veronica's fortune cookie had the numbers that won Hurley from Lost the lottery.
The X-Files
The mugshot of Malcolm T Wiggins from the X-Files episode "Titonus" appears on the wall of a police interrogation room in the Veronica Mars episode "Leave it to Beaver." Also the fictional car rental company Lariat where Mulder & Scully always rented their cars was featured prominently on the Veronica Mars episode "Rat Saw God."
CSI: Crime Scene Investigators
Morley cigarettes are smoked by Warrick Brown in a episode of Crime Scene Investigation.
Bones
An episode of Bones has a reference to a prostitute who worked at the (fictional and from the CSI universe) Tangiers hotel
Sleepy Hollow
Temperance and Booth from Bones team up with Icabod and Abbie from Sleepy Hollow on a case