COVID-19 has shrunk every carrier this year, but each carrier has taken their own approach at how much and where to trim flights. In April as passenger counts reached their nadir in the US, every major airline cut at least half of its departures. Southwest had by far the least cuts with "only" a 58.8% drop in flights year over year for April. Southwest still flew 45k flights in April, even though they only carried 537k passengers (or a little under 12 per flight). Compared to American (65.2% less flights), Delta (76.8% less), and United (82.6% less), Southwest held their service much higher than the other major airlines. Stats are for Mainline flights only.

Flight cuts were even deeper in May for all four major airlines, but Southwest still kept the highest percentage of mainline flights, flying 42k flights or a 62.6% drop compared to the May 2019 (AA -72.3%; DL -80.3%; UA -86.7%). While flights dropped, passengers flown started making a comeback in May. Southwest's passengers jumped to 1.9M in May. That 355% increase over April was much larger than the other major three airlines with American having the second biggest bump at 262%. But because Southwest was flying by far the most mainline flights, their flights had the lowest load factors in April (7.6%) and May (28.9%).

While Southwest cut more than half its flights in April and May, certain airport saw much more drastic cuts than others. When looking at Airports with the 15 most Southwest Passengers from 2019, all airports flew between 30-46% as the carrier cut flights across the board. In May, several airports started gaining flights back even while overall flights for Southwest continued to decrease. Year of year comparison of flights per month went up in May (compared to April) for ATL, LAS, DAL, BWI, MDW, and DEN with Denver leading the way moving up to 52.6% of 2019's May flight totals. Southwest's strategy appeared to focus on slowing adding flights to its more interior well established hubs while dropping flights to coastal destinations. California airports fared particularly poorly with LAX, SAN, OAK only flying 29.6%, 29.7%, and 32.5% of their 2019 domestic totals which were the worst three totals outside of San Juan that I looked at. You can take a look at the passenger and flight totals for each of the top 15 airports in April and May below.

Digging in closer at Southwest's STL route changes, we see flights dropping (almost) across all destinations in April and May. Pre-pandemic in February, Southwest was adding flights year-over-year at STL with some major (over 25% increase to a top 30 destination) adds to Dallas (DAL), Denver (DEN), Orlando (MCO), Phoenix (PHX), Nashville (BNA), and Tampa Bay (TPA). Below, I shown the year-over-year monthly flight comparisons for the top 30 Southwest destinations from STL for February through May. From the charts you can see flight cuts starting in March, accelerating in April, and hitting what appears to be the bottom in May with a significant amount of destinations being suspended. In May, 16 Destinations that had daily service from STL the previous May on Southwest were dropped due to COVID-19 (EWR was dropped earlier in the year).

While lots of destinations were cut entirely, a few outside of the top 30 actually saw a small increase with Des Moines (DSM 120 flights in May 2020/115 flights in May 2019), Wichita (ICT 118/113) and Panama City (ECP 71/66) all showing slight gains. Portland (PDX 60/62) and Sacramento (SMF 60/62) also basically matched 2019 numbers. Southwest clearly tried to maintain service at STL on many routes. While some of that effort may have been aimed at trying to maintain their brand presence at STL and other airports, it is hard to tell if that led to more passengers in May. DSM and ICT are two routes that stick out where Southwest kept twice daily service even though Load Factor on the routes in May were only 13.6% and 13.3%, respectively. The best performing routes from a Load Factor perspective in May were to either hubs or warm weather locations with roughly only once per day service. Nine destinations had above a 30% Load Factor in May with San Diego leading the way with 45.1% load factor over 60 flights. THe other destinations over 30% were RSW (43.8%), LAX (40.9%), HOU (40.7%), ATL (39.2%), SMF (37.0%), PHX (36.2%), ECP (34.7%), and TPA (31.9%).

Pre-pandemic, Southwest was in clear growth mode at STL, adding flights in January and February year-over-year. The below visual shows monthly percent change for domestic flights/passengers at all Southwest destinations and the monthly Load Factors. St. Louis was ranking well into the upper half of Southwest destinations early in the year. Once the pandemic hit, service to and from St. Louis by Southwest was maintained at a reasonable level, but compared to other Southwest destinations, St. Louis has ranked at about the median of all Southwest destinations in terms of percentage of flights cut compared to the previous year. In April Southwest flew 57.1% less flights to/from STL than in April 2019 which was the median value when comparing all Southwest destinations. In May, flights to/from STL were down 64.6%, just below the median value of 63.7%. While there are some interesting takeaways from the data so far, there is only so much insight that can be gleaned with the data through May. Once more data becomes available in the coming weeks to see June data, some more insights into how airlines are trying to bounce back will become clear. Ultimately, many efforts at maintaining service in April and May might have been focused on keeping customers long term (or just meeting minimum requirements to receive government assistance in some cases) and we will have to wait and see how that plays out. Please explore the visuals provided for more information about airline service and check back next month for more updates after June's data is made available by the Bureau of Transportation Statistics.