Southwest Airlines Co. provides revenue guidance for the first quarter 2019. The Company currently estimates first quarter 2019 RASM to increase in the 4% to 5% range, compared with first quarter 2018. The Company's outlook for first quarter 2019 RASM includes an estimated 1.5 point year-over-year benefit from its revenue management enhancements implemented in 2018, as well as an estimated 1.5 point year-over-year tailwind due to several items: its first quarter 2018 sub-optimal schedule from the accelerated retirement of its Boeing 737-300 (Classic) fleet; the prior year competitive fare environment; and the March 2018 Spring Break holiday shift impact. These expected year-over-year benefits to first quarter 2019 RASM are offset slightly by an estimated $40 million negative revenue impact in first quarter 2019 due to the timing shift of Easter to second quarter 2019.