I went to Ingonish beach,which is on the other side of Kelly's mountain in Cape Breton I was there for the day with family and friends,it was a nice warm day scattered clouds,I was lying on my back soaking up some sun talking to my nephew,we both could see a commercial plane flying by,fairly large one,may be a 747,anyway then as I started to look away to enjoy the rest of the sky I noticed something shine against the sun half hidden within the contrail from the plane,I then asked my nephew if he could see it and he said he could see it as well,it seemed to be fairly close behind the plane staying right in the contrail as if it was trying to hide,the shape was very odd,it looked like a rectangular shape each side left and right looking the same size but a section in the middle that seemed may be half the width of the 2 end sections,it was very interesting because I have never seen anything with that kind of detail in the day,sighting lasted 2 to 3 minutes .