Avianca SA, Colombia's largest airline, may return to the U.S. stock market with a public offering following its planned merger with El Salvador's Grupo Taca, according to a person familiar with the situation.

The companies announced plans Wednesday to combine, creating one of Latin America's largest airline groups with annual revenue of almost $3 billion and operations throughout the region.

Avianca delisted from the New York Stock Exchange when it filed for Chapter 11 protection in 2003. It emerged the following year after Brazil's Synergy Group fended off competing takeover offers from groups led by Avianca's pilots and Continental Airlines Inc. (CAL). It has been profitable ever since.

German Efromovich, the Bolivian-born businessman who controls Synergy, said Wednesday that an IPO was not imminent.

"All businessmen would see the stock market as a possible financing source, so we don't rule [it] out, but there are no immediate plans," he told Dow Jones Newswires.

However, four of Latin America's largest carriers already have U.S. listings: Lan Airlines SA (LAN-SGO), Copa Holdings SA (CPA), Tam SA (TAMM4-BS) and GOL Linhas Aereas Inteligentes SA (GOLL4-BS). Buoyant traffic growth in the region has made their market performance more resilient than American counterparts.

A source familiar with the Avianca-Taca plan said it was "fair to assume" that an IPO would be considered when the proposed merger had been completed and demonstrated synergies.

Avianca had taken steps to prepare for an IPO two years ago, but shelved the plan when markets soured, said another person familiar with its strategy.

The two airlines' owners reached agreement after a year of talks aimed at creating a regional carrier with more critical mass to compete with U.S. and European rivals on longhaul routes.

Taca built up a group of standalone carriers throughout central America, plus one in Peru, while Avianca also owns Brazil's OceanAir and Ecuador's VIP, which will be included in the joint holding company alongside Aerogal, another Ecuadorian carrier being acquired by Synergy.

The 25% stake held by Taca in Volaris, a Mexican airline, is not part of the deal, said a person familiar with the all-stock combination that would see Synergy hold two-thirds of the enlarged company.

The airlines will maintain their brands and operating certificates to comply with international rules governing ownership.

However, the partners see wide-ranging synergies, moving Avianca to an all-Airbus fleet to match Taca and Ocean Air.

Efromovich said he planned orders beyond those already placed by the partners. OceanAir's expansion includes 10 Airbus A350s to launch longhaul service.

Synergy, which has extensive energy assets in Latin America, did not hire investment bankers for the proposed deal, using Simpson Thacher & Bartlett and Gómez-Pinzón Zuleta as counsel. Taca was advised by Bank of America Merrill Lynch and Caoba Capital, with Greenberg Traurig as counsel.

-By Inti Landauro and Doug Cameron; Dow Jones Newswires; 57-1-610 70 44 Ext. 1131, colombia@dowjones.com