The plan, which will replace VCRs with digital servers on narrow-body aircraft, aims to lure more domestic travelers. Domestic flights account for more than 60 percent of United's capacity.

"There is no doubt that some of this work is overdue, and these efforts are critically important," UAL Chief Executive Glenn Tilton said on a recorded messages to employees.

UAL previously said it would spend USD$1.2 billion -- USD$550 million in 2007 and USD$650 million in 2008 -- to upgrade seats and make other improvements to its fleet.

United said it would add the digital video systems to 269 Airbus A320s and Boeing 757s as well as 20 767s and 777s.

UAL also said it would increase the number of "deep cleans" of aircraft by about 20 percent over the course of 2007.

In the last five years, many top airlines have restructured and begun investing heavily in various in-flight amenities in order to court well-heeled business travelers.

United and American Airlines, have devoted resources to improving their first- and business-class cabins on international flights. Such improvements include lie-flat seats.

Low-cost airlines such as Southwest Airlines have driven competition for domestic business travelers as well. American recently said it would work to become the first US carrier to offer Internet access on domestic flights.

(Reuters)