Frontier Airlines is adding a second daily flight this summer between Denver International Airport and St. Louis Lambert International Airport.

The second flight, beginning June 5, is scheduled on a 180-seat, A-320 aircraft.

Frontier currently offers daily roundtrip service on a 230-seat, A-321 aircraft.

The airline’s new daily roundtrip will add over 4,600 seats each way per month between Denver and St. Louis, officials said.

Denver-based Frontier announced March 13 it would end its daily…