Amid the gloom generated by last year's demise of Pan American World Airways and Eastern Airlines, and the resulting loss of nearly 15,000 airline jobs, Miami is seeing a flurry of airline activity this month.

Two carriers - Iberia Airlines, Spain's largest, and LTU International Airways, Germany's second-largest - are moving their North American headquarters from Los Angeles to Miami to take better advantage of the growing Latin American markets.Other carriers also are increasing their international presence in Miami.

"It appears the summer of 1992 will be the busiest summer to be experienced yet," said Frederick Elder, director of the Dade County Aviation Department.

Iberia projects it could triple its cargo movement through Miami by spring, increasing its daily shipments from 30,000 pounds to more than 100,000 pounds. Most of the European cargo moving through Miami is Italian-made footwear, handbags and machinery, such as auto parts.

"We'll be generating a lot more flights out of Miami," said Robert Illanes, Iberia's Los Angeles-based cargo traffic manager. "Miami will be our new cargo hub to Central, South and North America."

Iberia currently flies its Miami cargo on a DC-80, but the airline will be using two Boeing 747s and an additional 70 Miami cargo employees by April, Mr. Illanes said.

Key cargo markets will include the Dominican Republic, Guatemala, Honduras and Costa Rica.

Iberia has other U.S. cargo operations in Los Angeles, Chicago and New York, but what sets Miami apart is that the city is serving as the first U.S. hub for international operations for a European airline.

Latin American-bound cargo and passengers can connect through Miami to other Iberian flights or to those offered by its partners: Ladeco of Chile, Aerolineas Argentinas of Argentina and Viasa of Brazil.

Miami-Madrid service via Iberia soon will be offered twice daily, Mr. Elder said.

About 30 Iberia marketing, personnel and administrative employees will be transferring from Los Angeles to Miami.

Dusseldorf-based LTU is moving its sales and marketing headquarters and about 30 employees to downtown Miami by next month.

Now flying four times a week between Miami and Dusseldorf, Frankfurt and Munich, LTU plans to increase its Caribbean and Latin American service.

Judith Saxon, LTU station manager for North America, said a Miami base should improve communication to Europe and provide for better management over the Caribbean operations than does the Los Angeles location.

Although LTU's move to Miami will not affect cargo operations, passenger service will increase, Ms. Saxon said.

Other European carriers also are expanding from Miami. British Airways plans to offer twice-daily service to London. Lufthansa German Airlines is adding service to Hamburg, its fourth German city served from Miami, and has inaugurated a weekly Boeing 747 freighter service to Germany on Jan. 19.

Of the domestic carriers, United Airlines kicked off its Latin American service on Jan. 15 with a Miami-Caracas flight and it plans to launch service to Buenos Aires, Rio de Janiero and Sao Paulo on Jan. 31.