Portugal's government has approved the advancement of Synergy Aerospace to the next stage in the privatisation of flag-carrier TAP Portugal.
Synergy Aerospace is the investment group linked to Latin America's AviancaTaca.
No details of the potential sale price have been disclosed.
But Portugal's transport secretary, Sergio Monteiro, says the monetary value of the agreement "is not the most important criterion".
The government states that it has been establishing conditions for the next stages of the privatisation process, in order to safeguard the national interest.
It has already said it plans to prevent any single company taking a majority share in the loss-making carrier, and will cap the maximum stake at just under 50%.
In the first six months of this year TAP made a €112 million ($140 million) net loss.