We produced record first quarter revenue of $12.6 billion, up 3.1% year-over-year. Our adjusted EBITDAR margin was 7.6%, and we produced an adjusted operating margin of 0.6%. Our strong operational performance in the first quarter resulted in capacity that was up 8.5% year-over-year at the high end of our guidance range. Total revenue was approximately 0.5% higher than the midpoint of our January forecast. Unit revenue was down 4.9% year-over-year, slightly lower than the midpoint of our guidance on 1% higher ASMs. Our strong operational performance in the quarter also resulted in unit cost, excluding net special items and fuel on the low end of our guidance range, up 2.3% year-over-year. As a reminder, the first quarter of 2023 did not include the cost impact of our new pilot agreement, which resulted in a year-over-year headwind. Normalizing for this, our first quarter CASM ex would have been approximately flat year-over-year.
We have some modest updates to our fleet and CapEx guidance versus our March Investor Day update. For the year, we now expect to take delivery of 22 new mainline aircraft, down from our prior estimate of 29 aircraft. Our new aircraft deliveries include 16 737 MAX 8, 3 787-9s and 3 A321neos. We also plan to take delivery of 12 new Embraer E-175 aircraft. We continue to expect to grow full year capacity in line with our guidance above mid-single digits year-over-year. While Boeing delivery delays have impacted mainline capacity production, they have been largely offset by improvements in our regional aircraft utilization.
Aircraft delivery delays are impacting the entire industry, but they are not having the same impact on American as other carriers since we are not as dependent on new aircraft deliveries as most of our peers. We have modest aircraft CapEx requirements this decade due to our previous refleeting efforts. We now expect our 2024 aircraft CapEx to be approximately $2.2 billion, and our total CapEx to be approximately $3.1 billion. We continue to expect aircraft CapEx to be approximately $3 billion to $3.5 billion per year from 2025 through 2030. In the first quarter, we generated operating cash flows of $2.2 billion, and we produced free cash flow of $1.4 billion.
Our relatively low capital requirements and free cash flow production have allowed us to make significant progress toward strengthening the balance sheet. We reduced total debt by nearly $950 million in the first quarter and we have now reduced total debt by $12.3 billion from peak levels in 2021. Net debt is now at $33.4 billion, nearly $2 billion lower than pre-pandemic levels.
We continue to expect to be more than 85% of the way to our $15 billion total debt reduction goal by the end of this year. Now on to the outlook for the second quarter. Our focus continues to be on delivering industry-leading reliability, maximizing revenue and profitability and reengineer business which not only drives savings and greater productivity but also delivers a better experience for our customers and team members.
Our work to reengineer the business is progressing well, and we remain on track to deliver approximately $400 million in cost savings in 2024. Additionally, we continue to find opportunities to improve working capital. By the end of this year, we expect to have achieved approximately $200 million in incremental working capital improvements in addition to the $100 million we achieved in 2023.
At the Investor Day, we highlighted our goal to increase the production rate at our engine overhaul facility in Tulsa. And the team has done an incredible job accelerating that initiative this year. While this results in additional expense being pulled forward into 2024, the longer-term benefit of this project is materially NPV positive.
Our engine overhaul facility in Tulsa is a strategic asset and another competitive advantage for American in a constrained aircraft maintenance market. We plan to grow capacity at 7% to 9% year-over-year in the second quarter, primarily through improvements in aircraft utilization. Our capacity growth will slow considerably in the back half of the year, and we continue to expect to produce mid-single-digit capacity growth for the full year.
We expect second quarter TRASM to be down 1% to 3% versus 2023 with unit revenues inflecting positive year-over-year in the third quarter. We will continue to deliver strong unit cost performance in the second quarter with CASM ex expected to be up approximately 1% to 3% year-over-year. We still expect full year CASM-ex to be up approximately 0.5% to 3.5% despite a change in mix of flying with less mainline capacity and greater regional capacity production.
Our current forecast for the second quarter assumes a fuel price of between $2.75 and $2.95 per gallon. Based on our current demand assumptions and fuel price forecast, we expect to produce an adjusted operating margin of between 9.5% and 11.5% in the second quarter, and adjusted earnings per diluted share of between $1.15 and $1.45. The American Airlines team is focused on delivering results to unlock value in 2024 and beyond. We remain on track to deliver full year adjusted earnings per diluted share of between $2.25 and $3.25, and we continue to anticipate producing approximately $2 billion of free cash flow in 2024.
I’ll now turn it back to Robert for closing remarks.
Robert Isom: Thanks, Devon. As we outlined at our Investor Day last month, American has a changed airline with a strong foundation, and we’re well positioned to create value. We have a young and simplified fleet that continues to be a differentiating factor for American. We’re operating with excellence. We have built a strong network with fantastic partnerships around the globe and we’re engaging with customers through our industry-leading travel rewards program, demonstrating that life is better as an Advantage member.
We’re managing our unit costs better than our network peers, and we’re focused on reengineering our business improving asset utilization and enhancing productivity across the airline. These unique advantages have us well positioned to achieve our stated objectives this year and in the years ahead. All of this will result in margin expansion and growing free cash flow generation, creating value for our shareholders. We’re committed to delivering on what we said we would achieve, and we will provide updates on our progress along the way.
We have significant opportunities ahead of us, and we intend to take full advantage of those opportunities by leaning into our strengths and continuing to execute. As we move through the year, we will continue to leverage our fleet, network and rewards program and build on our strong operational momentum.
