The book Bellanca's Golden Age by Alan Abel and Drina Welch Abel has a short chapter on the company's "World War II Effort". It seems that Bellanca himself left to form an aviation department for Higgins Industries in New Orleans where he worked on the design of the Higgins-Bellanca Cargo Transport, which was designed to, among other things, transport a heavy tank and deliver it by parachute. After a couple of years the contract was cancelled.
The same source lists Bellanca as one of three companies building the Fairchild-designed AT-21 Gunnery Crew Trainer. It also say they built gun turrets for the PBM-3 and MARS seaplanes and "a large array of other important equipment required to win the war. Other World War II aircraft types flying Bellanca-built components and equipment also included the C-46, B-26, Helldiver, B-24, C-109 and the A-30."
Below is a link to a site with more info on the transport design.
http://retromechanix.com/higgins-bellanca-cargo-model-39-60-1944/Randy