Delta Air Lines Inc (NYSE: DAL) shares are retreating Monday. Berkshire Hathaway revealed a major new position in the airline.

The Omaha-based company built a position worth more than $2.6 billion, making Delta Berkshire's 14th-largest holding at the end of March.

Delta Air Lines Inc (NYSE: DAL) shares are retreating Monday. Berkshire Hathaway revealed a major new position in the airline.