With Spirit and Frontier coming together, everyone has focused on all the similarities… and to be fair, there are many. But the differences are also very telling. There is no place more interesting to see this dynamic than in Atlanta where both airlines have a large and growing operation.
Atlanta, of course, is the home to Delta’s massive hub and home base. Atlanta is the hub of airline dreams. It has a massive local market with a wealth of Fortune 500 companies to fill airplanes. It is also an ideally-located hub to feed the bottomless pit of demand that is Florida. Its current terminal layout which opened in 1980 is as good as it gets for a mega hub. With this, Delta has built a true monster of an operation.
In the past, there have been plenty of competitors in the market. After Eastern failed in early 1991, it was only a couple years until Valujet showed up. That airline was wildly successful, eventually becoming AirTran and proving to be a big thorn in Delta’s side. If Delta had any concerns once Southwest snapped up AirTran in 2011, it shouldn’t have. Southwest de-emphasized Atlanta quickly, keeping it as an important spoke and destination as part of its network but not the low fare be-all, end-all that it was under AirTran.
AirTran was at its peak carrying about a third of the local Atlanta passengers Delta carried domestically (according to Cirium DB1B data) and over 20 percent of what Delta carried out of Atlanta overall, including connections (according to Cirium T100 data). By 2019, Southwest was carrying about a quarter of the local traffic that Delta was taking, and its overall traffic was just over 10% of Delta’s.
Though Delta let AirTran in originally, it has been a fierce defender of the hub more often than not. Remember that second airport that they were working on in Atlanta? Delta had it murdered. Some of that red-tail ruthlessness has certainly lived on.
% of ATL Departing Traffic by Year

Fortunately for Frontier and Spirit, they don’t much care about that. Frontier has served Atlanta for ages, but originally mostly as a spoke from its Denver hub before it became a ULCC. Spirit entered the market in 2006. In that chart above, you can see those small slivers of green and yellow in the upper right. That still barely makes a dent, but with ultra low costs, both of these airlines think they can make a go of it under Delta’s high fare canopy. And schedules are increasingly rapidly for both airlines coming out of the pandemic.
It was 2013 when Frontier first ventured out beyond Denver with flights to Trenton. It added 5 more cities the next year, and as you’d expect with Frontier, there has been constant shifting of the actual destinations served. Frontier peaked in 2016, but then it pulled back. It came back in a big way in 2021, and it plans to be a whole lot bigger in 2022 with more than 30 destinations.
The only destinations that have been served every year since 2015? Cincinnati, Las Vegas, Miami, New York/LaGuardia, Orlando, Salt Lake, San Francisco, and yes, good ole’ Trenton. Those are actually a pretty good representation of Frontier’s sweet spot. It does a lot of West Coast, Northeast, and Florida/Caribbean.
Frontier and Spirit July 2022 Route Map From Atlanta

As the map shows, Spirit also does the Northeast, but it has a much bigger presence in the Midwest and Texas than Frontier. The route map is actually rather complementary, but it also beefs up flying to common cities of Baltimore, Cleveland, Dallas/Fort Worth, Detroit, Fort Lauderdale, Houston/IAH, Las Vegas, Miami, New Orleans, Newark, Orlando, Philadelphia, and Tampa.
The service pattern between the two airlines, however, is totally different.
Frontier and Spirit Departing Seats and Destinations From Atlanta

Spirit has a significantly higher frequency, and that’s where in this merger things will have to sort themselves out. I imagine we will continue to see Spirit’s high frequency pattern to the main markets in Florida and the Northeast. But you can then imagine Frontier’s lower frequency model layering in to serve other destinations. Together, it makes for an impressive footprint.
Atlanta is particularly interesting in this combined network since it is one of the few crew bases for both airlines. Frontier opened its crew base in late 2021 while Spirit just announced it will open a base in Atlanta later this year. They are both obviously very bullish and have plans to grow. Opening a crew base means Frontier is less likely to make a quick reversal in plans as it often does elsewhere.
Delta won’t like this, and it will undoubtedly try to be competitive. But with costs as low as Spirit and Frontier have, Delta will probably have a tough time keeping them down without diluting its own business. Frontier and Spirit are now big enough — and will have even more heft together — that the horse has already left the barn.