Low-cost carrier Frontier Airlines announced a major expansion with the addition of 21 new cities and 85 new routes to its network.

This increases the number of destinations the carrier serves by 30 percent and by the summer of 2018 will more than double the current number of total routes. Frontier is also expanding winter service to some warm weather destinations, such as Tampa (TPA), Miami (MIA), Orlando (MCO) and Fort Myers (RSW) in Florida, and Cancun (CUN), Mexico. See details on the new routes and service expansions here.

On the heels of the June launch of service between Seattle (SEA) and Austin (AUS) (and fresh from its Twitter dust up with Ann Coulter), Delta Air Lines announced a second daily flight between the two hipster cities to begin Oct. 1.

Delta will also add daily, non-stop service between Seattle and Medford (MFR), Ore., beginning Oct. 1 (details here), and daily, non-stop service between Los Angeles (LAX) and Mexico City (MEX) Dec. 1. Twice-daily nonstop flights between Boston (BOS) and Pittsburgh (PIT) start Oct. 1, with seasonal service between Boston and New Orleans (MSP) scheduled to kick off on Feb. 10, 2018. In addition, new service between Hartsfield-Jackson Atlanta International Airport and Shanghai Pudong International Airport is set to begin in July 2018. (More details here.)

Norwegian Air will begin flying between Austin and London Gatwick Airport (three times a week) beginning March 27, 2018, and between Denver International Airport and Paris Charles de Gaulle Airport starting April 9, 2018.

And JetBlue announced new routes for its premium Mint service, with service between Las Vegas (LAS) and Boston to begin Jan. 4, 2018, and between Seattle and Boston on Feb. 15, 2018. Details here.