The possibility that American Airlines might buy Northwest Airlines has raised questions about the future level of air service for the Twin Cities. A merger would leave American with 3 hubs in the Great Lakes region. When news of merger talks between Northwest and American came out last month..... many observers assumed the Minneapolis-St. Paul hub might have to go. But experts point to a number of factors suggesting the Twin Cities' would remain a hub and keep high levels of non-stop and frequent service. Minnesota Public Radio's Bill Catlin reports.