Can someone give me an idea what this is?

We were on vacation in Mexico in 1982. We flew from Cozemel to Chetineatza (sp?) for a day trip. Either my mother or father took this picture. Nothing was noticed by anyone at the time. All most twenty years later I scaned this picture to use as a wall paper on my computor. It was only then I saw the U shaped con-trail just above the pyramid. I make no claims as to what it might be. It does not match any surrounding cloud formations and looks like a con-trail to me but jets don't leave con-trails like that. I am hopeing some one can analize this picture and tell me what it is. Just below the con-trail there is what looks like a silver object.
Date is approximate.  Image sent to NUFORC indicates a u-shaped, or hook-shaped , contrail looking object in the sky, the approximate (apparent) size of the disc of the sun, or a bit larger.  PD