Passenger traffic at Des Moines International Airport grew by 12.4 percent in November over the same month last year largely because of a 19 percent gain in available plane seats, and the airport director expects another record passenger year as a result. Kevin Foley said the airport already is up 7.1 percent on passenger traffic for the year — more than double what was expected — and is likely to finish 2018 with 2.75 million passengers. The record set last year was 2.58 million. Operations director A.J. Graff told the airport authority board that the number of seats available on all flights was up a combined 19 percent in November and will be up about the same in December.