While we expect international RASMs will grow slower than domestic for a period, we also expect that international flying will have materially higher margins for United versus domestic in 2024 — or just less of a gap than in 2023. We, at United, have, I think, created a really very durable commercial model that has diversified our revenue streams and our network and largely de-commoditized our product versus just about every other airline in the US maybe with the exception of one. Our commercial strategy has resulted in fair levels at United just in not only for changes in price of fuel but also for the cost inputs at United, allowing us to overcome the inflationary cost pressures larger than we expected in 2023. You can see this in our relative revenue performance quarter-to-quarter.
United’s unique hub system in the largest US cities and the network we have built over decades from these hubs underpins our outlook and gives United access to revenues and profitable flying others simply do not have or have not been able to replicate. The United Next fleet growth in recent years has allowed us to unlock the true value in our hub system, which you can see from our results today. Unique aircraft cabin and capacity plans continue to be a driver of our strong revenue performance, particularly as demand for premium products remains elevated. For example, domestic premium revenue grew 13% year-over-year in Q4, over double the rate of coach, another data point validating our strategy. While we remain focused on monetizing our growing premium capacity, we also remain committed to Basic Economy.
Domestic Basic Economy revenue was up nearly 20% in the fourth quarter versus last year. Correct engage deficits at United remains a key component of the future. We continue to believe we can add gauge to domestic flying while maintaining strong unit revenues. Since 2019, United has increased its North American gauge by 22%, while also leading in PRASM growth. For 2024, we intend to focus much of our domestic growth in our Mid-Con hubs in Washington, Dallas, as we had significant levels of new connectivity. This connectivity change is why we have confidence in the RASM being accretive in 2024. Diversified revenue streams across our global network remain key to our relative success as we implement our United Next plans. United’s global network is a key structural advantage we will focus on in the coming years and it differentiates us.
With that, I wanted to say thanks to the entire United team and hand it over to Mike to discuss our financial results. Mike?
Mike Leskinen: Thanks, Andrew, and thank you to the whole United team for closing up the year on a high note, both operationally and financially. I’m proud to report that in 2023 we delivered pretax income of $4.3 billion, a more than $3.2 billion improvement over 2022. We delivered earnings per share of $10.05 within our initial guidance range of $10 to $12, and well ahead of consensus expectations of about $6 at the beginning of the year. We achieved this despite significant industry headwinds and operational constraints that led to lower capacity. For the fourth quarter, we delivered pretax income of $845 million and earnings per share of $2, ahead of consensus and above the high end of our guidance range. Strong operational performance, robust revenue trends and a decrease in fuel prices supported these results.
Fourth quarter CASM-ex was up 4.9% as we did not operate flight to Tel Aviv for the full quarter. Additionally, effective with the fourth quarter, we are now classifying certain commissions that has been classified as contra-revenue and distribution expense. This has no impact on net income or cash flow. This change added 1 point to our year-on-year fourth quarter CASM-ex and increased fourth quarter year-on-year unit revenue by 0.6 points. The change will also result in an approximate 1 point headwind to year-on-year CASM-ex and an approximate 0.6 point increase in RASM through the end of the third quarter of this year. Underlying unit costs trended favorably during the quarter as the completion factor came in better than planned due to our strong operational performance.
Compared to 2019, our relative performance on CASM-ex was near the top of the industry. As Scott outlined, delivering strong relative cost performance remains critical to the successful execution of United Next. We have always ascertained the costs that are borne by the entire industry are passed along in prices with a lag. Historically, this relationship has been clear with jet fuel prices. More recently, the relationship has been clear for both higher labor and higher maintenance costs as well. Notably, our unit cost in 2023 were up 17.8% versus 2019 compared to ultra low cost carriers, unit costs that are expected to be up 25% on average. That more than 7 point cost convergence in costs occurred simultaneous with an emerging preference for United product, the top-tier operational reliability that United provides.
