Is Delta Air Lines downgrading jets at Minneapolis-St. Paul airport?

The Star Tribune reports the Atlanta-based airline appears to be swapping newer Airbus planes with older Boeing or McDonnell Douglas jets at MSP. Delta told the newspaper, "We always work to deploy the most efficient aircraft to each route, which is critical to the success of our hub at MSP." Some travelers and airport officials have complained the older planes are noisier and more cramped.