Investigation of aircraft overflight and ground vehicle noise around a general aviation airport provided the opportunity to measure the frontyard to backyard noise reduction afforded by residential structures for these two types of noise sources. The measured average noise reduction for two residences using passing street vehicles as noise sources was found to be 17 and 21 dBA. For aircraft overflights using identical measurement instrumentation and microphone locations, as were used for the street traffic noise, the average measured noise reduction (i.e., difference between frontyard and backyard noise levels) was found to be 0.2 and 0.4 dBA. The results of the measurements show that acoustical factors around residences are such as to generally cause substantial frontyard to backyard noise reduction for street traffic noise, but not for the noise from aircraft overflights.