Airlines serving L.A. experience some ups and downs; list rankings reflect changes in competitive industry.

The highly competitive nature of the airline industry is reflected in this week's List of the 25 largest passenger carriers serving Los Angeles County airports.

Over the past 12 months, the industry has played a game of musical chairs with almost half the spots on The List shifting players. The changes in ranking range from shifts on the top of The List down to the bottom, where an international airline was bumped because of the entry of a regional line -- Reno Air.

In the meantime, the total number of passengers carried by the 25 largest airlines remained flat in 1993 compared to 1992 traffic, according to figures supplied by the carriers.

The List, based on 1993 passengers, shows the largest airlines with flights in Los Angeles carried a total of 47.37 million customers. In 1992, the largest carriers served roughly the same number of passengers.

The number includes passengers who got on and off commercial flights at Los Angeles International Airport, as well as Burbank-Glendale-Pasadena, Long Beach and Palmdale airports.

The ranking does not include passenger traffic in 1994, which has improved over 1993 as the economy has turned around.

According to The List, Chicago-based United Airlines continues to be the biggest carrier serving Los Angeles County airports. And the airline is getting bigger here.

United served nearly 9.7 million passengers in the county last year, for a market share of 20.4 percent.

In 1992, United served 8.8 million passengers in the county with a 18.6 percent market share.

The figures for United do not include the carrier's new intrastate Shuttle service that was started earlier this year.

The continued growth of Southwest Airlines as both a national and local presence shows up on The List with the carrier moving into the No. 2 spot from No. 4 on a similar ranking published by the Business Journal a year ago.

In 1993, Southwest served 6.7 million passengers in Los Angeles County with a market share of 14.2 percent, compared to 4.9 million passengers in 1992 with a market share of 10.5 percent.

Southwest's move into the No. 2 spot pushed Delta Airlines down a notch to No. 3 and American Airlines to No. 4.

In recent years, Southwest has shown steady growth by marketing itself as a low-cost, no-frills carrier. Based in Dallas, the carrier offers flights to big and small cities throughout the Southwest but in recent months has started to expand nationally.

From Los Angeles, the carrier's primary destinations are Las Vegas and San Francisco.

In 1992, Southwest was No. 10 on The List, which was based on passenger traffic in 1991.

Further down on The List's top 10 carriers, Alaska Airlines and Trans World Airlines swapped places from a year ago. Alaska moved into the No. 9 spot and TWA dropped to No. 10.

Alaska reported serving 1.4 million passengers in 1993 compared to 1.6 million in 1992, while TWA's local business dropped from 1.7 million to 1.3 million customers.

In the second tier of carriers (Nos. 11 through 20) the List's only new entrant appears -- No. 16 Reno Air.

Reno Air, which did not appear on last year's List, moved into the ranking with 507,971 passengers in 1993 and a market share of 1.1 percent. Reno Air, based in Reno, Nev., operates out of LAX and Burbank.

The emergence of Reno Air onto The List pushed off Cathay Pacific. Cathay, an international carrier serving Pacific Rim countries, was No. 25 on last year's 1993 List.

Though all of the List's top 10 carriers are domestic airlines, the rest of the ranking is made up largely of foreign-based airlines. The large number of overseas carriers operating in the county reflect LAX's strong position as an international gateway.