Unidentified object photographed near Madrid, Spain

“I was out in the field, to take some sunset pictures, on Monday, January 25, 2010, in a place 30 kms East from Madrid, Spain, near Torrejon Air Base.
I made about 160 pictures for more or less one hour. I didn’t notice anything strange, I had been in that place at least a dozen times before.
When I checked the pictures the next day, right in the second picture I found a speck that I took for a bird at first. Taking a closer look, I realized that it wasn’t a bird, but an object that reflected the sun’s rays.
I took other pictures of birds and airplanes passing by, just for fun, and I have included them in the PPS show attached.
I’ve been a glider pilot since 1991, and I know local types of airplanes and birds. I cannot tell what’s on this single picture.
I am interested to know if there are other pictures that might show some resemblance with this craft, that would be quite definitive.