La dee dah-FLOTUS will return with POTUS

  Apparently she was going to stay and enjoy a few more hours at Martha's Vineyard; obviously that would have had further political implications, in addition to the other times when she left early, forcing the Air Force to make more than one trip to cart the royal First Family around the country. WHD:

Bringing Mrs. Obama home a day later would have forced the Secret Service to continue to provide security on Martha’s Vineyard even though the president would be back in Washington. And Mrs. Obama would have again billed the Air Force for a separate, specially equipped jet to take her home.

  This beats the time they flew Bo the dog separately, a fact which Snopes refutes with the excuse that the Obamas needed several planes and Bo's planes had presidential aides on board. Perhaps this was because Bo doesn't have a pilot's license. 
  The president's plane on that trip seated 6-19 people; therefore the dog would not fit. 
  Presumably those extra 13 people were displaced by luggage.
  Lots and lots of luggage.