Another cool plane...Convair B-58 Hustler. The large pod underneath the fuselage contained most of the fuel and the nuclear weapons. It dropped away over the target allowing the plane to be cleaner, lighter and faster on the return trip to base.
Designed for high altitude and high speed, it was later switched to lower altitudes when Russian SAMs advanced to the point where it was considered vulnerable. The aircraft wasn't well suited to this role and when combined with it's accident history and with high operating costs, they were retired. The F-111 filled this role later on.