Consistent, reproducible forecasting models for general aviation activity at airports are important in statewide airport planning since more than 80 percent of the operations at major airports are by geneal aviation aircraft. During the state airport system planning process in Iowa, current general aviation forecasting tools were evaluated and a survey was designed to study the aviation operations at several airports where continuous count data were not availabe. The methodology developed for forecasting annual general aviation operations, passenger enplanements, and peak-hour movements are discussed. Data for 1971, 1975, and 1976 were available from several nontowered and towered airports and indicate that general aviation operations per based aircraft declined at both classes of airports. The general aviation operation models, developed from 1975 survey data, predicted operations in 1976 within 7 percent; the differences were not statistically significant./Author/