Delta Air Lines expects both unit revenue and unit costs to near the top of its most recent first-quarter (Q1) guidance ranges, with strong system-wide demand and improving yields providing tailwinds, while accelerated depreciation and pay raises added costs compared to year-earlier figures.

Q1 unit revenue, or total revenue per available seat mile (TRASM), is expected to be up 5% compared to Q1 2017, at 16.40 cents, the carrier said in an investor update. Delta’s TRASM excludes third-party sales from its oil refinery.

Delta said strong demand generated “positive results” in “all geographic entities,” adding that international unit revenue out-performed domestic.

CASM ex-fuel and profit-sharing is expected to be up 4% year-over-year (YOY), “driven by wage increases in April 2017 and accelerated depreciation due to aircraft retirements,” Delta said. Delta’s full-year 2018 CASM-ex fuel target is a 0-2% YOY increase—a plan that assumes Q1 would see the highest YOY jump. Q1 fuel cost is expected to be $2.00-2.05/gal., down from January guidance but in line with the most recent insight, provided at mid-March investor conference update.

Meanwhile, the carrier’s first-quarter operating statistics saw system RPMs increase 2.8% YOY on a 2.7% capacity increase. Domestic RPMs were up 3.6%, while international RPMs edged up 1.2%.

Delta boosted domestic capacity 4.2% YOY in the quarter, while international ASMs grew just 0.2%. The geographic capacity disparity highlights a trend that is seeing U.S. majors focus on fortifying domestic strongholds rather than chasing higher-unit-revenue international business.

Delta’s Q1 international ASM changes saw a 2% decline in the Pacific and a 1.4% dip in Latin America. Atlantic was up 2.9%.