Regional carrier Republic Airways' passenger traffic declined 7% in March compared to a year earlier.
Capacity at the Indianapolis-based carrier fell 10%, while consolidated load factor rose by three percentage points to 83%.
Republic carried 2.65 million passengers in March, up 1% year-on-year.
Republic Airways owns Chautauqua Airlines, Frontier Airlines, Republic Airlines and Shuttle America.
Traffic and capacity numbers were modified on 5 April with updated numbers from Republic.