Adrian, out of curiousity I searched "MexicoCity UFO sightings" on Google. The incident I mentioned was on 24June05, not the 1991 sighting you alluded to.

Further, one of the curious things about trying to research some of the sightings is I can't access the films or pictures for many of them - except in the debunk files. Which also maybe because of my internet settings (security), but why then does it note that those depicting numerous sources of a said sighting (s) no longer exist or are no longer available?

fyi: http://www.ufoinfo.com/sightings/mexico.shtml

That pesky planet Venus has been very busy, in Mexico and else where..

http://www.rense.com

What was it Fox Mulder use to say? I want to believe? Maybe not, but with such a variety of "odd" balls from Astronauts to farmers tp Presidents claiming sightings of craft not accountable on our little planet .... one might consider keeping an open mind.

Still, when one does consider the time factor for such a craft to transverse space to reach this wee rock in the universe ... it does give one pause about the number of these sightings; and the why, wherefore, or reason for them.