Prospective memory is the ability to remember to perform acts in the future and is essential in the aviation domain because it supports remembering to complete radio communications. In the laboratory younger adults tend to outperform older adults on prospective memory tasks; yet in naturalistic settings older adults perform as well as younger adults. Lower workload from background tasks and the habitual nature of the tasks are suggested reasons for the improved performance by older adults. We tested this notion using a Cessna 172 simulator to examine radio communication completion rates of 45 pilots. We found that older pilots had significantly lower communication task completion rates than younger pilots in both the low and high workload conditions. Multiple regression identified age and working memory as predictors of prospective memory performance in the low workload condition and working memory and recent pilot-in-command hours as predictors in the high workload condition.