The 99th Airlift Squadron, however, is part of the 89th Airlift Wing at Joint Base Andrews. This Wing also includes the 1st Airlift Squadron, which flies C-32A and C-40 aircraft, and the Presidential Airlift Group, responsible for operating the highly specialized VC-25A aircraft , better known as Air Force One.

There is no indication of who might be on board. The video from the 21st only shows the jet taxiing to the end of the runway, waiting for clearance to take off, and then departing.

Plane spotters using online tracking software watched the C-37A, serial number 99-0404 and assigned the 99th Airlift Squadron , using the callsign SAM003, leaving Joint Base Andrews, situated just outside of Washington, D.C., and heading south on Dec. 20, 2018. A PTZtv webcam at Saint Martin's Princess Juliana International Airport recorded video of the jet taking off again on Dec. 21, 2018 and listened in on air traffic control conversations with the crew, who were using the same callsign.

Washington, D.C. has been aflutter this week with a burst of major year-end news on U.S. government foreign and domestic policy issues . Now, a partial government shutdown seeming inevitable, right in time for the peak of the holiday season. But yesterday, a U.S. Air Force C-37A Gulfstream V VIP jet, part a unit that caters to senior members of the executive branch and Congress, flew from the nation's capital down to the island of Saint Martin in the Caribbean.

Collectively, the 89th's mission is to provide world-class VIP airlift for the president, the vice president, cabinet members, congressional delegations, other senior officials and foreign dignitaries. C-37As have a very comfortable interior and a flight attendant to cater to passenger's needs. This is known as the as a "Special Air Mission," or SAM, as seen in the callsign 99-0404 was using on its way to and from Saint Martin. Trump is still in D.C. due to the possible government shutdown, but First Lady Melania and their son Barron could have headed to the island to start a holiday vacation early. The president has a villa there, though he has been trying to sell it and you can now stay there through Airbnb for around $11,000 a night. The president and his family had been set to take a 16-day holiday to the Mar-a-Lago resort, which now appears to have gotten delayed by the budget showdown.

USAF The inside of one of the 99th Airlift Wing's C-37As.

Other members of Trump's cabinet or other senior officials might have taken the trip, as well. Various members of the Trump Administration have weathered criticism over the past two years for using government aircraft to take trips of dubious official value. In a particularly controversial instance in August 2017, Treasury Secretary Steve Mnuchin, his wife, Louise Linton, Senate Majority Leader Mitch McConnell, a Republican from Kentucky, and others flew to Fort Knox ostensibly to review the nation's gold stockpile there. It also happened to be a prime location to view a solar eclipse. A C-37B jet, similar to the A model, but based on the Gulfstream 550 business jet, flew Mnunchin, Linton, and others to Fort Knox at a cost of nearly $27,000 dollars. The Treasury Secretary later reimbursed the U.S. government for his wife's travel costs. This and other flights prompted an investigation into Mnuchin's travel that found there wasn't anything explicitly illegal about the flights, which had a combined cost of around $811,000, but questioned their necessity.

USAF Air Force flight attendants assigned the 99th Airlift Squadron prepare food on board a C-20B, another Gulfstream variant similar to the C-37A, during a training mission in 2017.

It could also be a more mundane flight for training or other purposes. Jets from the 99th will sometimes fly "off station" training missions to foreign airports. This provides an opportunity "for pilots to fine-tune their approaches and landings, perfect for communications systems operators to upgrade or gain certifications," according to the Air Force. But considering wide swathes of the federal government looks to be shutting down in the coming hours, a nasty pill for government workers to swallow over the Christmas holiday, the flight seems particularly interesting. It would be interesting to know who exactly jetted off to Caribbean paradise aboard a government GV, if indeed anyone was onboard, and what their official purpose was for doing so. We've reached out to the 89th Airlift Wing already to see if they can give us more information about the holiday flight to Saint Martin. We'll be sure to keep you updated when and if we get any more details. Update: 10:35pm EST— Well, it wasn't Melania and Barron, who took an 89th Airlift Wing C-32A to Mar-a-Lago, as planned, but without President Trump.

Contact the author: jtrevithickpr@gmail.com