Aspergillus fumigatus is a filamentous fungus commonly found in compost piles, but also ubiquitously throughout the environment. Importantly, it is a major causative agent of pulmonary fungal diseases, including invasive aspergillosis (IA), chronic pulmonary aspergillosis (CPA), aspergillomas, and allergic bronchopulmonary aspergillosis (ABPA). Despite overall effectiveness against asexual spores (conidia) in vitro, antifungal treatments often fail to improve overall health outcomes in treated patients. There are many potential reasons behind treatment failures, including a change in the nutritional environment, accessibility of the drug to the fungus, complex microbial communities, and different stages of growth of the fungus in the lung vs. in vitro. In the mammalian lung, A. fumigatus grows as a complex network of hyphae that may form biofilms. Features of A. fumigatus biofilms include production of an extracellular matrix, adherence to surfaces, and most importantly, reduced susceptibility to antifungal drug treatment. Classical in vitro antifungal drug testing occurs on A. fumigatus conidia; however, conidia are not the morphotype of the fungus treated during clinical infection which are highlighted by the formation of biofilms. Therefore, methods to grow and assess damage to A. fumigatus biofilms in vitro are critical in determining the effectiveness of both contemporary antifungal drugs and investigational molecules at different stages of drug development. Here, we review novel methods of growing A. fumigatus submerged biofilms in vitro and a variety of methods that can be utilized to assess the effect of molecules on the fungal biofilm including metabolic activity, lysis, membrane permeability, biofilm biomass reduction, and biofilm recovery after damage. These assays are expected to better inform potential efficacy of contemporary and novel antifungal treatments.