Brazilian carrier Azul SA and the principal shareholder for rival Gol Linhas Aereas Inteligentes SA reached an agreement to work toward a merger, potentially creating one of the largest airlines in Latin America.

Abra—which also controls Colombia’s flag carrier Avianca—and Azul concluded the two Brazilian airlines have 90% complimentary and non-overlapping routes. Last year, amid reports that Azul was interested in merging with its rival GOL, the airlines launched a domestic codeshare.

Azul and Gol shares rose sharply on Thursday, following the announcement of a proposed merger between the two Brazilian airlines. Azul’s stock price rose by more than 4%, while Gol’s shares jumped by about 8%.

Shares of Azul (NYSE:AZUL) climbed 3% in US premarket trading following the announcement of significant progress towards a potential merger with GOL.