On january 4th, 2018 my husband and i were on a private jet flying from seattle washington to lakeland florida. there were four people on the flight, the pilot , the co-pilot, my husband and myself. there were multiple small screens in the cabin that showed a map of the u.S., the planes location, flight path, altitude and air speed. about 1:00 pm we were flying over wyoming. our altitude was 45,000 ft and air speed was around 520 mph. the sky was a crystal clear vi blue and we seemed to be the only thing in the sky. i was sitting in my seat on the left hand side of the plane looking out of the window when something to my upper left hand side field of vision caught my eye. sitting there, just as plain as day, was an babsolutely enormous craft of some kind. it was a dark dull grey in color,disc shaped with a dome on top and underneath. the domes were almost as tall as the craft was wide. i remember thinking that it looked rather “clumsy” instead of sleek like the ones i’d seen on tv. it appeared to be motionless with no apparent exhaust or gasses. again, i want to emphasize the size of the thing. allowing for a distance of 5 to 6 miles from uss it must have been at least 5 football fields wide and almost the same in height. i called my husband to hurry over and have a look. we both starred at it speechless for about a minute. he then ran up to the flight deck and asked the pilot and co-pilot to to look and see if they could identify it. there we all were, dumbstruck looking out of the plane’s windows at something that looked totally foreign and out of place. we asked if they knew what it might be or if they had ever seen anything remotely like it before. keep in mind, these were two seasoned experienced pilots who had flown for a very respectable company for many years. they said they had absolutely no idea what it was and that they had never seen anything like it before. we all continued to watch it as we passed by and eventually left it behind . the rest of the flight was uneventful. oh, we did ask the pilots if they were going to report seeing the craft and they said absolutely not. more than their jobs were worth i guess.