The Friday File: Through 12/31/15, 80% of the adult US population had taken at least one airplane trip in their life, up from 49% in 1971. Last year, 45% of the adult US population flew compared to 21% in 1971. Of those having flown, the average number of trips taken in 2015 was 4.8, with 31% taking one trip and 15% taking nine or more. 63% of trips were domestic.