NEW YORK ( TheStreet) -- Continuing its methodical build-up in New York, Delta ( DAL) said Monday it will code-share with new partner Virgin Atlantic on 108 routes and, most importantly, on nine daily flights between New York airports and London's Heathrow Airport. Delta opened its new $1.4 billion JFK terminal on May 24. The terminal, as gleaming and inviting and full of food options as it is, has lacked one thing: frequent service to London Heathrow, the favorite international destination for New Yorkers. Currently, Delta has three daily departures from JFK to Heathrow. By contrast, rival American ( AAMRQ.PK) operates four daily departures from JFK to Heathrow, while its code-share and joint venture partner British Airways operates eight. British Airways also operates three daily departures from Newark to Heathrow. New York/Heathrow expansion was a principal reason for Delta's December deal to acquire 49% of Virgin Atlantic. Speaking at an investor conference in March, Delta President Ed Bastian said the route "is the driving force behind our investment decision at Virgin Atlantic." Now, the Delta code will be on six additional New York/London routes, including four daily Virgin flights from JFK to Heathrow and two daily Virgin flights from Newark to Heathrow. That will give Delta passengers nine daily options to get from New York to Heathrow and seven daily options from JFK. Overall, Virgin Atlantic will put its code on 91 Delta routes, including both trans-Atlantic and domestic U.S. routes, while Delta will place its code on 17 Virgin Atlantic routes, including Little Red routes connecting London to Manchester, Edinburgh and Aberdeen. Codeshares enable airlines to allow passengers to book flights on each other's Web sites. The Delta/Virgin Atlantic codeshares will take effect July 3, with codeshare booking available starting June 29. Starting then, customers can decide where they want to accumulate frequent flier miles. Besides the flights from Heathrow to the New York area, Delta will also be able to put its code on Virgin Atlantic Heathrow flights serving six U.S. airports -- Boston, Washington Dulles, Los Angeles, Miami, Chicago and San Francisco, as well as Vancouver, Canada. Delta has said it would begin Heathrow-Seattle service if the joint venture is approved.