Unlike Other US Carriers: Why Delta’s Fleet Is So Airbus-Heavy

On January 12th, Delta Air Lines announced that it was ordering 20 Airbus A350-1000s. When they enter service, the aircraft will be the largest Delta's fleet. The jets look to be the carrier's flagship type, complete with its highest-end premium products. Interestingly, with the addition of the A350-1000, Delta will operate much of Airbus' in-production aircraft, from the small Airbus A220-100 to the A350-1000. So, while the other major US carriers seem to be loyal to Boeing, why does Delta buck the trend and go with aircraft from the European planemaker?