Why Delta and Skyteam need the Virgin Atlantic partnership and Heathrow slots

Skift Take
Delta operates routes from Heathrow with Air France-KLM, but a Virgin partnership would really put a little sizzle into Delta's slots at the airport.
Delta Air Lines and its Skyteam partners are slot paupers at London Heathrow, and that's an overriding reason why Delta is thought to be in the advanced stages of talks to buy Singapore Airlines' 49% stake in Virgin Atlantic Airways.
Skift analyzed the 2012-2013 winter allocations at Heathrow by airline alliance using data from Airport Coordination Ltd., a UK-based, airline-owned company responsible for coordinating slots at Heathrow and 29 other airports in Europe, North America, and the Middle East.
The allocations in the charts below are the weekly slot designations for airlines and alliances at Heathrow for winter 2012-2013, and the numb