That's virtually impossible. IND is near to ORD, and if anything UAL will build up schedules at ORD where it already has a well-developed hub. Besides, IND is a medium-sized airport and O'Hare is a world titan. But IND could stand to gain additional maintenance work, if UAL hangs onto US's 737s for awhile.
Anyway, the buyout would hurt consumers badly. The Justice Department should can it so fast that Jim Goodwin couldn't even say "paint job." The major airlines have demonstrated clearly that they abuse medium-sized and small cities with high fares whenever they get a chance. If anything, Justice should hit American with huge fines in the Vanguard suit. Putting American's head on a pike would be a much-needed warning to the other major airlines--including United and US Airways.
Need a new airline paint scheme? Better call Saul! (Bass that is)