weak excuse.... the graduation was mid morning and the service started at 2pm in louisville.
the flight time is about 90 minutes and The President of The United States can command any flight/air space and local street traffic if he so wishes. Plus he has a Marine one helicopters at his disposal to get to and from ceremony to ceremony after getting on and off Air Force One. Should have put his fam on the jet and paid his respects after the graduation.
Obama attends Malia's high school graduation - CNNPolitics.com
But he was the highest-profile guest at the mid-morning ceremony, held on the school's campus in Washington's leafy Northwest quadrant. The First Lady and Malia's sister Sasha, who turned 15 on Friday, were also expected the attend.
Memorial Service | Muhammad Ali Center - Louisville, KY
The service will be open to the public and will begin at 2:00 p.m.