This study investigates the determinants of air traffic volumes and structure (carrier type) at lesser studied small European airports serving below one million passengers per annum. It discusses airport choice factors for airline customers and focuses on the characteristics of small airports and their catchment areas in order to explain variation in 2016 traffic volumes for 146 regional gateways in 21 EU countries. Through the application of multiple linear regression and correlation it is found that population size, airport charges and the need for capacity coordination are the most related to the number of passengers using these airports. Several different correlations are found with respect to the share of low-cost, full-service and charter carriers as a proportion of total airport traffic, which in most cases extends the findings of the limited number of other studies in the field of small regional airports. The research concludes that while certain relationships can be found, their statistical significance is moderate, leaving scope for a deeper study into a smaller samples of airports.