US regulators have tentatively approved a controversial joint venture between Delta Air Lines and Aeromexico, on the condition that the two SkyTeam carriers divest 30 slot pairs at Mexico City and New York John F Kennedy airports.

The US Department of Transportation (DOT) has also conditioned its approval of anti-trust immunity for the two airlines to just five years, among other conditions.

"We tentatively conclude that, as conditioned, the alliance will not substantially reduce or eliminate competition," says the DOT.

However, it acknowledges concerns that the partnership will limit competition at Mexico City and New York JFK airports, and has called on the airlines to divest 24 slot pairs at Mexico City and six slot pairs at JFK.

"This remedy would allow for new, competitive entry at these airports that would not otherwise be possible," says the DOT.

The agency proposes limiting the grant of anti-trust approval to five years, and says the airlines will be required to remove certain anti-competitive provisions from their alliance agreements.

Delta and Aeromexico did not immediately comment on the tentative DOT approval.

The proposed joint venture had attracted opposition from several US and Mexican carriers, who believe that the partnership will restrict access to the Mexico City airport, where slots are already difficult to obtain.

Mexican regulators approved the joint venture in May, with the condition that the two airlines give up eight slot pairs at Mexico City. The DOT says the slot divestitures it called for will include the eight slot pairs, subject to approval by both US and Mexican regulators.

Source: Cirium Dashboard