Original sentence: () is an aviation holding corporation based in Indianapolis, Indiana, which owns three regional airlines operating in the United States: Chautauqua Airlines, Republic Airlines, and Shuttle America and is in process of acquiring two major airlines: Frontier Airlines and Midwest Airlines.Republic Airways Holdings also retains a 50% ownership stake in Mokulele Airlines
Edited sentence: () is an aviation holding corporation based in Indianapolis, Indiana, which owns four airlines operating in the United States: Chautauqua Airlines, Midwest Airlines, Republic Airlines, and Shuttle America and is in process of acquiring Frontier Airlines.Republic Airways Holdings also retains a 89% ownership stake in Mokulele Airlines