Delta Air Lines said it will shut down its Erlanger, Ky.-based regional carrier subsidiary Comair, as Delta significantly pares back its flying of small regional jets.

Comair is one of a number of Delta Connection regional feeder carriers, and makes up about 1 percent of Delta's flight capacity, according to Atlanta-based Delta.

Delta said the discontinuation of Comair operations after Sept. 29 "will not result in any significant changes in Delta's network," with no disruption to customers. The airline added that Cincinnati "will continue to be an important market in Delta's worldwide network."

Comair had been gradually shrinking over the years, along with Delta's presence at its Cincinnati hub where Comair had its major presence. Comair operates some of the oldest 50-seat regional jets in the Delta Connection fleet, according to a memo from Comair president Ryan Gumm to employees. In the memo he called the decision to cease operations "an unfortunate necessity due to the economic limitations of our aging aircraft, cost structure, the long-term outlook for 50-seat aircraft, and our challenging industry and economy."

The move comes as Delta plans to reduce its fleet of 50-seat regional jets from nearly 350 to 125, enabled by a recently approved pilot labor contract and a deal to lease from rival Southwest Airlines all of the Boeing 717s Southwest inherited through its acquisition of AirTran Airways.