With the orders announced Wednesday, as well as the Boeing 747-400s, 737-300s and 757s ordered earlier by United, the airline has 469 new aircraft on order or option--more than its entire current fleet of 412 planes.
Wolf said that there would be an "orderly" phaseout of of the older planes as the new ones are delivered. However, the overall fleet will be expanded. As a result, he said, United's fleet would grow significantly.
He said that the average age of United's fleet, currently 13.5 years and one of the oldest in the industry, would decline fairly rapidly. Currently the industry average age of planes is 11.7. Eastern Airlines has the oldest fleet at 14.6 years while Delta Airlines has the youngest at 8.5 years.
The firm orders for 737 models will be delivered between July of 1991 and July of 1995 and the options, if they are taken, between 1995 and 1998. They will be powered by engines made by General Electric Co.
The 757 firm orders will be delivered between February, 1991, and August, 1993, and the options will be delivered between August, 1993, and February, 1996. They will be powered by Pratt & Whitney engines.
Times staff writer Ralph Vartabedian contributed to this story.