Delta Air Lines gained antitrust clearance from the U.S. Justice Department and the European Commission for a deal to buy a 49 percent stake in British carrier Virgin Atlantic.

The cross-border investment in magnate Richard Branson’s Virgin Atlantic, along with a proposed joint venture between the two carriers, is aimed at enabling Delta to fill a weak spot in its network: London Heathrow Airport, a crucial point on the map for the lucrative business traveler market.

Atlanta-based Delta is limited in how many flights it can add at Heathrow on its own because the airport limits flying rights, called slots.

Delta six months ago announced the deal to buy the stake in Virgin Atlantic from Singapore Airlines for $360 million. Branson’s Virgin Group will maintain a 51 percent stake.

The Justice Department’s antitrust division said it completed a “thorough investigation of the competitive effects” of the proposed investment and joint venture. The European Commission — the European Union’s executive body — issued a written statement saying its investigation showed that “in all markets the combined entity would continue to face competition from several strong competitors, notably British Airways and American Airlines,” and that the proposed deal did not raise competition concerns.

Delta still awaits antitrust immunity approval from the U.S. Department of Transportation for the proposed joint venture. Delta said it expects the joint venture approval later this year, and plans to close the acquisition before then.