This collection contains considerable material relating to aviation history, particularly in western and northern Canada, including material on: the Keng Wah Aviation School for Nationalist Chinese pilots; the RCAF; illustrations of the technology of flight; reference material; and microfilms of the Hudson Strait Expedition fonds (1927-1928) and "The Bulletin" (Western Canada Airways, 1929-1937). Additionally, there is material on Tweddell's other research interests, notably aerial mapping and surveying.

The fonds includes paintings, sketches and memorabilia relating to the artistic pursuits and output of Olena (Sherven) Smith; and material relating to Tom Smith’s careers and interests, particularly archaeology and local history, as well as engineering and farming, including documentation of his job on the engineering crew for the Alaska Highway.