Robert Kraft traveled on Air Force One.in his Air Force 1s.
After Air Force One landed at Andrews Air Force base in Maryland, Kraft was seen disembarking the plane.
The billionaire buisnessman was photographed alongside Trump as the president addressed reporters on board Air Force One on Sunday.
Kraft was also seen following Trump into the White House shortly before 7 p.m. Sunday.
Kraft is a lifelong Democrat but jumped ship during the recent campaign to back Trump, his longtime friend. After Kraft's late wife, Myra, died in 2011, Trump was very supportive of Kraft.
"He called me once a week for the whole year, the most depressing year of my life when I was down and out", Kraft said at the time.
The president has spoken about his friendship with Kraft, Patriots coach Bill Belichick and star quarterback Tom Brady on several occasions.
Kraft then added: 'He was one of five or six people that were like that.
The move came after Trump spent the weekend at his Mar-a-Lago estate in Florida - where Kraft in February joined Trump, Prime Minister Shinzo Abe of Japan, and their wives for dinner.
Kraft was one of Trump's guests at the inauguration, where he had a good, close-up view of his friend taking the oath of office.