Strange triangular craft over Highway 57 outside of Luxemburg, WI glowing orange and pulsatingMy girlfriend and I were enroute to Green Bay, WI having came from Sand Bay, which is just southwest of Sturgeon Bay, WI. We were heading south on state highway 57 passing Luxemburg,WI at County Road S. My girlfriend pointed up through the top of the windshield and asked "what the heck is that?" At this point we observed a orange in color glowing object flying directly above us headed in the opposite direction. My first thought was that this may be some sort of ultralight aircraft, however there are no known landing strips in the vicinity. To my knowledge ultralight aircraft do not glow and pulsate. This object was triangular in shape and did not act as a conventional aircraft. I looked in my rear view mirror as i continued south on state highway 57 and observed this craft veer up and down and take an immediate left turn above the treeline viewed from my rear view mirror, a left turn as a car or truck would. It was not something any aircraf! t i have ever seen could maneuver. While i continued driving my girlfriend turned around and continued to observe this object as it appeared to have descended beneath the tree line.I have been to several Expermental Aircraft Association fly-ins at Wittman Regional Airport in Oshkosh, Wisconsin and never have i observed an ultralight aircraft make the maneuvers that this object did.Background: (me) small business owner, property maintenance manager (my girlfriend) criminal justice major, customer service representative Neither of us have ever witnessed a "ufo" or anything that we could not dismiss as being something "natural". This incident took us completely by surprise. I have been looking all over the internet to see if anyone else noticed this object in the sky as there were approximately 15-20 other vehicles within a mile radius travelling north and south.