Republic Airways Holdings Inc., which owns Midwest and Frontier airlines, said Thursday it has agreed to buy up to 40 new Bombardier CS300 jets, with options for an additional 40 aircraft.

The aircraft, which will be configured with seating for 138 passengers, are scheduled for delivery beginning in the second quarter of 2015.

Republic, based in Indianapolis, has signed an 15-year maintenance contract with Pratt & Whitney for upkeep of the engines.