Core Viewpoint - Delta Air Lines reported mixed fourth-quarter results, exceeding profit expectations but missing revenue forecasts, leading to a decline in share price by approximately 3% intraday Financial Performance - Adjusted earnings for the December quarter were $1.55 per share, slightly above the consensus estimate of $1.52 [2] - Total revenue for the quarter was $14.61 billion, falling short of analysts' expectations of $14.72 billion [2] - Revenue growth was impacted by approximately two percentage points due to the government shutdown, which primarily affected domestic travel demand [2] - Quarterly revenue increased by 1.2% year over year, supported by a capacity growth of 1.3% [3] - For the full year 2025, Delta achieved record revenue of $58.3 billion, a 2.3% increase from 2024 [3] - Revenue from diversified streams, including premium services, cargo, and maintenance operations, rose by 7% year over year, accounting for 60% of total revenue [3] Future Guidance - Delta forecasts first-quarter 2026 revenue growth of 5% to 7% year over year, with operating margins expected between 4.5% and 6% [4] - Projected first-quarter earnings per share are estimated to be between $0.50 and $0.90, compared to consensus expectations of $0.72 [4] - For the full year 2026, Delta anticipates earnings of $6.50 to $7.50 per share, indicating approximately 20% growth at the midpoint from 2025 levels, but below the Street consensus of $7.32 [4] Strategic Developments - Delta announced a new agreement with Boeing to purchase 30 Boeing 787-10 widebody aircraft, with options for an additional 30 planes, with deliveries scheduled to begin in 2031 [5]

Core Viewpoint - The company initially adopted Rust for its advantages in speed, safety, and modernity, but ultimately banned its use due to the discomfort it caused within the organization by exposing inefficiencies and raising performance expectations [1][22][28]. Group 1: Initial Adoption of Rust - Rust was seen as an ideal choice for the company, promising rapid development and safety features [2][6]. - The first service rewritten in Rust was a high-traffic application that had significant memory leak issues, which Rust effectively resolved, leading to impressive performance metrics [7][17]. Group 2: Consequences of Using Rust - The development speed increased dramatically, with new features being developed in just three months, which was deemed unacceptable by management [10]. - The ease of hiring Rust developers led to an influx of highly qualified candidates, making existing engineers feel inadequate [12][14]. - The internal toolchain was found lacking compared to Rust's ecosystem, highlighting organizational inefficiencies [15][16]. Group 3: Organizational Response - The CTO held a meeting questioning if the company would still be bogged down by bugs and technical debt without Rust, leading to a decision to ban its use [20][21]. - The decision was framed as a response to Rust's ability to expose the company's inefficiencies and elevate performance standards that the organization was not ready to meet [22][28]. Group 4: Aftermath and Reflection - Following the ban, 90% of services reverted to using Go, which was seen as adequately slow and safe, aligning with the company's strategic approach to managing technical debt [23]. - The company expressed regret over the decision only when stability was desired, indicating a complex relationship with the efficiency Rust brought [25][26].