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.

A new study shows airlines lost fewer than nine bags per thousand passengers last year, compared to more than 18 bags five years ago. The New York Times reports Delta Air Lines, the dominant carrier at the Minneapolis-St. Paul International Airport, is among the leaders using new technology to reduce mishandled baggage. The airline has made major upgrades to its tag printers, bag readers and conveyor belts at hubs in Atlanta and Los Angeles. Similar upgrades are also planned in New York.

Delta will pay $150 million for a refinery near Philadelphia, according to the Associated Press. The airline hopes to cut fuel costs by making its own jet fuel.

Atlanta-based Delta Air Lines -- the dominate carrier at the Minneapolis-St. Paul International Airport -- will lease 88 Boeing 717 planes from Dallas-based Southwest Airlines. The aircraft will be transferred starting next year, with 16 scheduled to arrive next year. Another 36 will come in 2014 and the rest will be delivered in 2015.

The Atlanta-based carrier is looking into using crude oil from western North Dakota to supply its new refinery in Pennsylvania, the Associated Press reports. Delta Air Lines bought the refinery near Philadelphia from Phillips 66 for $150 million in May with hopes of cutting fuel costs by making its own jet fuel.