Avianca is emerging as the second-largest airline group in Latin America behind the newly formed Latam Group, created through the merger of LAN Airlines and TAM Airlines.

But linking up networks with TAP will require more effort than might be expected. TAP's Latin American network is focused on Brazil, where the Synergy Group's exposure is limited to Ocean Air. Both AviancaTACA's base, at Bogota's El Dorado International Airport, and TAP's, at Lisbon Portela Airport, are capacity constrained, despite the fact that Bogota just opened a new international terminal. But, infrastructure deficiencies aside, the two airports could serve as strengthened gateways once TAP is integrated.

One of the most interesting aspects of the proposed transaction is how it will be implemented legally. After all, the EU limit on foreign ownership is still 49%, and even though there are aspirations to relax restrictions, changes would hinge on international agreements. According to industry sources, Synergy Group already controls a Portuguese air operator certificate. Also, Efromovich reportedly holds a Polish passport in addition to his Bolivian one, enabling him to act as an EU citizen. Efromovich could not be reached for comment.

The planned takeover is also welcome news for the Star Alliance, which is facing the exit of TAM Brazil as a result of its merger with LAN this year. Chilean antitrust authorities requested that TAM Brazil make the move within two years of the merger's closing. Star could retain access to Brazil if TAM opts to stay out of LAN's Oneworld. While the Colombian economy is rebounding as the state continues to recover control over security from drug cartels, Avianca cannot fully replace TAM, which is based in the continent's largest air transport market. Also, Bogota's El Dorado Airport is still a bottleneck and needs further upgrades.

Meanwhile, in a domestic situation in Europe that involves no foreign investment, Aegean Airlines has launched another attempt to take over its domestic rival, Olympic Air. The deal, signed Oct. 22, still hinges on regulatory approval.

Both Greek carriers have suffered tremendously from the economic downturn caused by the country's dramatic debt crisis. Greece has been in recession for five years, and demand for air travel has been receding. Aegean is posting big losses but, following serious restructuring, Olympic is close to breakeven.

Aegean has tried to merge with or take over Olympic at least twice. When the former national carrier was privatized in 2009, the government chose a bid by the Marfin Investment Fund over Aegean's. The airlines subsequently reached a preliminary agreement on a merger, but the proposal was blocked in 2011 by the European Commission because it would have led to what was effectively a monopoly on domestic routes.

Almost two years later, the carriers are trying again. They hope new competition in the Greek domestic market from Cyprus Airways will ease antitrust concerns. Also, because the two airlines' combined revenues are less than €2.5 billion ($33 billion), the case would be handled by Greek rather than European competition authorities.

According to industry sources, Olympic would focus on regional and domestic flying, including public service obligation routes to maintain air links to many small Greek islands. Aegean would serve European routes.