Due to pressurisation concerns, a United Airlines flight, US 1186, was forced to make an emergency landing at Austin-Bergstrom International Airport on July 24. The event generated an Alert 2 alert, and the Boeing 747, carrying 112 people, was forced to return to the gate shortly after departure.

High temperatures make air less dense, reducing engine performance and the amount of lift produced at a given speed. That generally means lower takeoff weights and longer takeoff distances are needed to produce sufficient lift.

U.S. airlines have sparred with the administration in recent years over responsibility for flight delays, passenger rights, landing slots and other issues.

United announced its largest-ever South Pacific schedule a few months ago. Across the Atlantic, United also has the most extensive network, 10% greater than the next American carrier.

The recent delays were driven mostly by a series of rolling storms coupled with other issues like a shortage of air traffic controllers in congested airspace around New York and other areas, derailing travel plans of thousands of customers.