On a commercial flight from salt lake city airport to o'hare airport in chicago on a business trip, i saw an unexplained aircraft that passed from the front of our plane to the rear of our plane on the right side of the plane. thus, this unusual aircraft was traveling from east to west and was situated over the airspace of the state of utah. the date of the commercial flight was january 31, 2020. there was an unusual amount of cloud cover beneath the plane the entire length of the trip from salt lake city to chicago, which could be confirmed with independently retrieved meteorological reports for that day. i was taking photographs with my ipad mini out the window of the aircraft, as i was securely situated in a window seat directly above the wing of the plane. the flight had taken off from the salt lake city airport and was on its route to chicago. the stewardess was already starting the first food service during the flight. the pilot deliberately appeared to slow the plane down, as it was clearly evident that he was pressing on the brake, and this slowed flight path lasted for quite some time. i have provided the flight number and ticket information for my business itinerary to mufon directly it is possible to perform private investigations utilizing that information as a foundation. during this slowed down flight time, i heard a loud, prolonged buzzing sound in front of the plane and i looked out the window of the plane in an attempt to determine the potential cause for the buzzing sound. approximately 10 seconds later an aircraft shaped like a large cylindrical tube passed by the plane at the same altitude as our commercial aircraft. this unknown aircraft was directly outside the window from my plane seat above the wing. however, there were no wings on this unknown aircraft and there was no means of visible propulsion such as an engine. there were also no flashing lights that are typically required for commercial aircraft, which is a violation of faa requirements. in addition to the buzzing sound as this unknown aircraft passed by our commercial aircraft, there was the sound of displaced air which created a sustained whooshing sound, which would confirm that the unknown aircraft was solid in nature. the main cylindrical body for this unknown aircraft appeared to be beige in color, but it also appeared to be metallic in structure. when it started to pass, i noted that there were some protrusions on the bottom of this unknown aircraft but those protrusions were not wings. there was also a bent red tube with connected segments that connected the protrusion from the bottom of this unknown aircraft to the cylindrical tube shape for the main body of the aircraft. i did not observe any feature that would resemble a cockpit, so there was no opportunity to observe a pilot at all. on the front of the unknown aircraft, there was some small structure, which might have been the cockpit but it appeared to be dark in color, and i did not get a clear look at it. there was no symbols or insignia at all on this unknown aircraft. i estimate that the size of this unknown aircraft was approximately 1/6th the entire length of the our commercial aircraft and it passed within 200 to 250 feet of our commercial aircraft. as i indicated, this unknown aircraft did not have any wings, because if it did, its wings might have touched the wings of our commercial aircraft. this unknown aircraft was that close to our aircraft. so, as this unknown aircraft passed our commercial plane, i attempted to jump up from my seat to turn around and look at it through the windows of our aircraft seats behind me. i was still in my seat-belt so i could not jump up too far, but i could turn around and turn my head to look at it. i did see it pass through the other windows of our aircraft. there was no trail emitted by the unknown aircraft as it passed. i did not have time to see the back of the unknown ship after it passed. was this unknown aircraft a black budget project from the military or was it an actual unidentified flying object? was it coincidental that the coronovirus pandemic started to spread in the united states, and that there was an earthquake in utah a short time later? i do not have any way of knowing whether there are any connections between these two events. i am interested in knowing why the pilot deliberately slowed down the flight in our commercial aircraft in that particular area? was it because the pilot was "instructed" to slow down the commercial plane because he was told that something would be passing us from the front of the plane to the back of the plane? if this was the reason why the plane deliberately slowed down then this would suggest that the pilot was aware of the approaching unknown aircraft and all that this meaning entails. an alternative explanation is because of the proximity to the mountain range below in utah, or because of the plane was approaching colorado airspace? is there a standing requirement to slow down commercial aircraft in this particular airspace over utah? there was a point while the plane was deliberately slowed down by the pilot that i thought that i should place my ipad on the airplane window and should start the video feature and to even use up the entire hard drive to video everything that was going on outside. however, i got distracted by the factor that the first food service was starting so i did not do so. in addition, i thought that there would have been a legitimate reason why the plane had been deliberately slowed down by the pilot because the plane had slowed down as well when traveling from chicago to salt lake city. there is no doubt that our commercial airplane was in airspace for the state of utah because i had taken some photographs with my ipad shortly before the unknown aircraft passed our commercial aircraft from the front of the plane to the back of the plane. at the time of the last photograph, there were still gaps in the clouds over utah, as the solid base of clouds beneath our commercial aircraft had not yet appeared (img_0424). the reason why this is important is that there were definitive geological/topographical structures beneath our commercial aircraft that could be readily identifiable by an expert looking at a map. i have attached the original photograph directly from my ipad and a screenshot from mapquest of that same structure. i have also included a photograph out my window seat above the wing of our commercial aircraft (img_0420 and img_0421). after i downloaded the photographs from the ipad to my personal laptop, i attempted to submit each digital photograph to a website that extracts the exif metadata from the photograph, which includes the gps coordinates. one such application is known as pic2map.Com, which would provide the exact locations in which a photograph was taken. however, upon utilizing this web application, i noted that the gps coordinates were blank and then remembered that i changed the settings on my ipad to prevent tracking. i set the ipad to prevent tracking to protect my privacy, as i was attending a class in computer security. as a result, the location where the photograph was taken from the sky above could be derived from the geographical landmarks below. there is a "y"-shaped joining of highways or rivers that could be clearly seen through the clouds, and this geographical landmark tentatively places the location of the plane within utah airspace (img_0424). it could be many possible geographical feature so additional investigation is required. another web application to view metadata from a digital photograph is available at: http://exif.Regex.Info/exif.Cgi. i am relieved to have finally described what happened during my return business trip from salt lake city to chicago. i observed what appeared to be an unknown aircraft that could have either been a classified military black project with a new means of propulsion that did not require wings or a typical engine or i observed something else entirely. i decided to bring this report forward to mufon because there is the possibility that others on the right side of the commercial aircraft who had their window blinds up at the time might have seen this unknown aircraft as well and might also come forward. if this unknown aircraft is seen again in the airspace over utah or even other states, then at least this report will be on record as a point of comparison.