It is a flight jacket worn over a Vault 34 jumpsuit, the jacket has many U.S. military medal ribbons and insignia stitched onto it along with a necklace of bullet casings. It has the same general shape as the Tunnel Snake outfit from Fallout 3.
The medals worn on the flight suit are: the Silver Star, the Good Conduct Medal, and the Distinguished Flying Cross. The Good Conduct Medal is the US Army version, and not the version used by the Air Force.
The ribbons on the flight suit are: the Aerial Achievement Medal, the Silver Star, the Defense Superior Service Medal, the Defense Distinguished Service Medal, the Legion of Merit, the Outstanding Airman of the Year ribbon, the Airman's Medal, the Bronze Star, the Joint Meritorious Unit Award, the Air Force Outstanding Unit Award, the Combat Readiness Medal, the Air Reserve Forces Meritorious Service Medal, the Purple Heart, the Defense Meritorious Service Medal, the Air Force Good Conduct Medal, the Joint Service Commendation Medal, the Air Force Commendation Medal, and the Prisoner of War Medal.
While all the ribbons are actually used by the US military, under current uniform regulations ribbons and medals are not authorized for wear on anything besides Service Dress.