According to the site's fluff:
Piloted by Babylon 5's first commander, Jeffery Sinclair, this craft is a good example of customized markings. They reflect the Sinclair family history, a tradition of flying fighters that stretches all the way back to the Battle of Britain in WWII. The bold chevron's are the most personal component, representing the markings his father's fighter wore in the Dilgar war. The port 'wing' carries two other notable markings: a service badge for Sinclair's participation at The Line and a set of "invasion stripes*", which commemorate the first Sinclair fighter pilot.
*Found this on a WWII site:
"...during the planning of the Normandy landings, allied commanders feared the possibility of tremendous aircraft losses due to friendly fire. Something had to be done to avoid confusion. Therefore, it was decided to mark every aircraft operating over the beaches with distinctive black and white stripes around the wings and the fuselages. "