Some experts say a merger between US Airways and American Airlines may create the world's largest airline, but also would present challenges. "The challenge is to integrate the workforces. And US Airways to date hasn't been able to do that with its America West merger," said Eric Smith, a bankruptcy and aviation attorney. However, Bob Herbst, an airline industry analyst and founder of AirlineFinancials.com, said, "Total cost-saving synergies [equal] $1.8 billion to $2.5 billion accretive within 12 months of merger. ... It's the opinion of AirlineFinancials.com that American and US Airways must merge to remain long-term competitive."