Aerial surveys can be used to detect and monitor lesser prairie-chicken (Tympanuchus pallidicinctus) leks, but the need exists to understand the response of lesser prairie-chickens to survey aircraft. We conducted lek surveys in Texas and New Mexico, USA, using an R-22 Beta II helicopter and R-44 Raven II helicopter. We observed the behavior of lesser prairie-chickens at 44 leks during aerial lek surveys. We observed flush responses of 38.5% (20.2–59.4%; 95% CI) and 50.0% (26.0–74.0%) from the R-22 and R-44, respectively. We found no difference in flush response between helicopter types (P = 0.326). We used logistic regression models to predict lesser prairie-chicken flush response to aerial surveys. We found that distance from the transect was the most important flush response predictor during helicopter surveys. When flushed, lesser prairie-chickens returned to the lek and resumed predisturbance behavior in 7.0 ± 2.6 min (mean ± 95% CI). Our results suggest aerial surveys can be conducted without disruption to the lesser prairie-chicken lek dynamic. © 2011 The Wildlife Society.