Delta Air Lines on Tuesday said it has sought bids from regional carriers to operate up to 143 jets for its Delta Connection service, as the bankrupt airline looks to cut costs.

The airline, which has 450 regional jets flying under the Delta Connection banner, also said it is looking to start offering first-class seats on the service.

Delta contracts out flying from smaller markets to regional airlines, buying their seats and selling them under its banner.

Delta said it is seeking bids for up to 43 70-seat aircraft and up to 50 50-seat jets to replace flying covered by existing contracts.

Additionally, it is seeking bids for up to 50 76-seat aircraft featuring first-class seats.

Delta unit Comair, Republic Airways subsidiaries Chautauqua Airlines and Shuttle America, and Mesa Air Group's Freedom Airlines have the contracts that Delta wants to replace.

Atlanta-based Delta, which filed for bankruptcy protection in September last year, has said it needs to raise USD$3 billion annually through revenue increases and cost cuts to survive.