But Southwest keeps addingDEN routes

Southwest Airlines has announced another spurt of growth at Denver International Airport, while Frontier Airlines – which recently filed for Chapter 11 reorganization -- has announced some cutbacks. Southwest said it will add two new routes from Denver on June 4: Portland, Ore. and Indianapolis, each with two flights a day. On the same date, Southwest will add an eighth daily DEN-Las Vegas roundtrip, and on August 23 it will add a second daily flight between Denver and El Paso. This is all in addition to Southwest’s previously announced plans for a May 10 expansion at Denver, when it will begin new service to Los Angeles International (five daily flights), Philadelphia, Raleigh-Durham, San Antonio, San Jose and St. Louis.

Denver-based Frontier, meanwhile, said it is ending its code-share partnership with Republic Airlines, which devotes a dozen regional jets to Frontier’s route network. “With current economic conditions and other business changes, we have been forced to drastically rethink the use of regional aircraft in our fleet mix,” Frontier said. The partnership will be phased out by mid-June. As part of the changes, Frontier will not begin new service from Denver to Missoula on May 16 as previously planned. It will also end service to Sioux City, Iowa on May 12; to Jacksonville, Fla. on May 31; and to Little Rock, Memphis and Tulsa on June 1. On the plus side, Frontier’s Lynx Aviation unit just began new daily service between Denver and Durango, Colo., using a Q400.