Early on in the Trump administration, two top Cabinet officials had reportedly agreed to coordinate their travel schedules so that at least one of them would remain in the U.S. to respond to sudden announcements.

Early on in the Trump administration, two top Cabinet officials had reportedly agreed to coordinate their travel schedules so that at least one of them would remain in the U.S. to respond to sudden announcements, notes the Associated Press.
The two men were said to be defense secretary James Mattis and Trump’s newly sworn-in chief of staff John Kelly who was homeland security secretary at the time. 
According to the Associated Press, “Mattis and Kelly...agreed in the earliest weeks of Trump's presidency that one of them should remain in the United States at all times to keep tabs on the orders rapidly emerging from the White House, according to a person familiar with the discussions.” 
The president has a noted appreciation for generals; in addition to Mattis and Kelly, he chose H.R. McMaster to be his national security adviser after retired Lieutenant General Michael Flynn was ousted, notes Slate. 
During Kelly's swearing-in ceremony Monday, Trump said, "He will do a spectacular job, I have no doubt, as Chief of Staff. What he's done in terms of Homeland Security is record-shattering -- if you look at the border, you look at the tremendous results we've had, and you look at the spirit. And with a very controversial situation, there's been very little controversy -- which is pretty amazing by itself."
The president continued, "So I want to congratulate you on having done a fantastic job, General. And we look forward to, if it's possible, an even better job as Chief of Staff."