Community noise caused by aircraft traffic is examined in relation to its estimation by predictive and measurement methods. The basic properties of the noise exposure at any airport-vicinity site are shown to be mainly defined by the statistics of the peak-level occurrence and noise duration distributions over a given time period. The relationship between these distributions is derived in terms of traffic parameters. This leads to the derivation of an equation for the evaluation of Leq , which makes use of information usually acquired for an NNI assessment and which is directly comparable with the NNI formula. An important result of the study is the development of a simple and convenient method for predicting aircraft noise exposures, by which various noise indices (NNI, Leq, LNP, L10 etc.) can be directly evaluated.