US domestic aviation: the Big 3 and LCCs fine tune their goals

The three large US global network airlines and Southwest and Spirit Airlines have differing outlooks for domestic revenue growth in 2Q2018. Although their international entities will lead revenue generation for American, Delta and United, their domestic operations are expected to sustain their positive unit revenue generation.

There are many reasons unique to Southwest for its projected unit revenue decline in 2Q2018, including some booking pressure resulting from the mid-Apr-2017 incident, when a fan blade broke off one its 737's engines on a flight from New York to Dallas.

The airline is also operating a less than ideal schedule due to the retirement of its Boeing 737-300 Classic fleet. Southwest believes 2Q2018 will mean a bottoming out of its revenue performance, but admits it is off-plan in its revenue generation.
Spirit has faced discounting for the better part of year, and now appears to be working to shore up its non-ticket revenue, forecasting that it can reach USD55 per passenger in 2018.

It is too early to determine the specific effects of the roll-out of Basic Economy pricing by the US full service airlines, but those fare segments are no doubt creating a different pricing dynamic in the US domestic market.