Live news: S&P 500 notches first 3-day winning streak of 2024

United Airlines said it had its “busiest travel period in history” in late December, a highlight in forecast-beating fourth-quarter results that helped send shares higher in after-hours trading.

However, the Chicago-based airline warned that the recent grounding of its fleet of Boeing 737 MAX 9 jets would result in a deeper adjusted loss in its first quarter than Wall Street expected.

United flew 8.2mn customers in the final fortnight of 2023 — an average of 483,000 each day — as it reported net income of $1.81 a share on $13.6bn in revenue in the three months ended December 31.

The beat helped push shares more than 7 per cent in after-hours trading. United holds its earnings call on Tuesday morning.