Delta to Forge Partnership With Virgin Atlantic : Airlines: Alliance would give the U.S. carrier access to London’s coveted Heathrow Airport and enable the company’s Southland customers to fly non-stop.

In the latest global airline alliance to take shape, Delta Air Lines and Britain’s Virgin Atlantic Airways agreed Tuesday to forge a partnership that would give Delta access to London’s highly coveted Heathrow Airport.

Delta would become the fourth major U.S. carrier--after American, United and USAir--to serve Heathrow, by marketing and selling seats on Virgin’s transatlantic flights from Los Angeles, San Francisco and New York.

The partnership between cautious and conservative Delta and quirky Virgin--which employs masseuses on some flights and plans to begin in-flight video gambling--would include a code-sharing agreement allowing Delta to market and sell Virgin’s transatlantic flights as if they were its own.

Delta’s Southern California passengers would be able to fly Virgin’s daily nonstop flights to Heathrow while earning Delta frequent-flier miles. They now must fly Delta to London’s secondary airport, Gatwick, via Atlanta or Cincinnati.

Virgin, which is owned by flamboyant British entrepreneur Richard Branson, would receive about $150 million a year by selling blocks of seats to Delta. The two airlines expect to merge their frequent-flier programs in July and start their code sharing in November.

The alliance, which must be approved by U.S. and British authorities, would also include Virgin’s flights to Gatwick from Boston, Miami and Orlando.

Delta already serves Gatwick, but Heathrow is the preference for frequent business travelers and others making connections to the rest of Britain or Europe. Delta has been blocked from entering Heathrow by British restrictions on foreign carriers.

“It fills a competitive void in Delta’s transatlantic operations by giving us access to Heathrow for the first time, and it teams Virgin with a major U.S. partner,” Delta Chairman and President Ronald W. Allen said in a statement. “This promises to strengthen competition among all carriers serving the U.S. and U.K.”

The deal would make Virgin much more competitive with far larger archrival British Airways, industry analysts said.

“It gives them a leg up on the American market,” analyst Ernest Arvai said. “It’s hard for Virgin to stand alone” against British Airways, which has its own code-sharing arrangement with USAir.

Although passengers would fly on Virgin, Delta would advertise the flights separately and determine the price of the Virgin seats it has purchased in advance.

Travel agents expect Delta and Virgin to cut fares and begin other promotions to launch the partnership in November.

“It makes Delta and Virgin very competitive,” said Thomas Nulty, president of Santa Ana-based Associated Travel Management. “It will keep American, United and British Airways on their toes.”