Not a planefag and thought this might merit a look by those more knowledgeable than I am:
Last night just before 10pm mountain time a Dassault Falcon 8X (OO-HHO) from Geneva, Switzerland landed at one of the General Aviation airports in the suburbs of Denver, CO. This is a very rare, and possibly unprecedented occurrence, as the GA reliever airports in the Denver metro are not really equipped to receive international flights, especially that late at night. This is a very large aircraft for a GA reliever airport. It's curious that this flight did not fly into DIA, which is better equipped to receive international flights. I wonder if the passengers wanted to avoid using DIA.
https://flightaware.com/live/flight/OOHHO