Executives blamed unusually poor weather, the air-traffic control system and the refusal of many pilots, who are angry about the slow pace of contract negotiations, to fly overtime.
Armada of 80,000 vehicles, 658 planes moves more than 7.5 million shipments daily; operates own air traffic control system, weather monitoring service.
"The problem isn't the weather, it's the air traffic control system's inability to deal with the weather," he said.
The airline blames unusually bad weather and the air traffic control system for most of its difficulties.
In 1967 the site was upgraded with the air-transportable all-weather AN/TSQ-81 radar bombing control system.
Some industry observers, like Michael Boyd of the Boyd Group Consultancy in Evergreen, Colo., say blame for the problems lies not so much with the airlines — big or small — or the weather as with the air traffic control system itself.
United attributes its poor performance to a stretch of unusually bad weather and an outmoded air traffic control system that it and other airlines complain is not up to the task of managing an air transport network carrying twice as many passengers as it did 20 years ago.
Airlines usually blame bad weather for problems, and given that the air traffic control system is stretched to its limits, weather can cause excessive delays, even in the fall, said David L. Beckerman, the director of consulting services at Back Aviation Solutions.
The industry estimates that delays attributable to the air traffic control system, as opposed to weather, cost airlines and their passengers some $6 billion a year in lost productivity.
It lists various dangers to American drones, including "air defense threats", "jamming of UAV sensor systems", "terrestrial weather", and "electronic warfare employed against the command and control system".
