I am compelled to offer a few tidbits concerning the 'missile theory.' The primary reason for this trend of explanation seems to be two-fold; first, there is the report indicating an 'explosion' within or near the aircraft and second, some witnesses reported seeing a 'line of fire' in the sky at around the time of the crash. Coupled with the lack of immediate witnesses, the story sounds as good as any other if you stick to these facts; plus, we all know the government likes to test its anti-aircraft warfare systems at night with no warning in crowded air traffic lanes hard up against one of the most populated coastlines in the country.

Okay. A brief bit of back-of-the-envelope analysis follows.

Engagement Envelope. Every SAM has an 'engagement envelope,' which is a range of distances to and speeds of the target within which it is able to engage said target. Bluntly, if a target is too far away and/or going too fast, the missile won't have enough delta-v to reach its target and will either fall to the ground or in some cases refuse to launch. In this case, the fact that the aircraft had spent several minutes at 13,000 feet just prior to the incident means that MANPADS is out. There are few (if any) man-portable SAM systems that can engage a fast-moving target (i.e. faster than a helicopter) at that speed and that altitude.

Damage Profile. MANPADS and other IR SAMs are unlikely for another reason - the location of the explosion. The NTSB report states that the explosion occured near Row 23 within the fuselage. The wreckage shows that the explosion threw pieces of the airplane out rather than punched the skin inward. Infrared seeking missiles will detonate on or near the engines of the target; that's what they are homing on. Even those with logic contained in the fusing designed to increase the chances of a fuselage hit aren't given the profiles of airliners; at most, they will attempt to strike forward of the 'hot spot' - which is where the body of a warplane is. In addition, no fragments of any weapon were found - and even more than a bomb on board, a missile would leave pieces of itself in the area and embedded in the target.

Radar SAM Requirements. Of course, radar-guided missiles would tend towards the center of the target. There are a few problems with this solution, however. Radar-guided SAMS are (with a very few exceptions) not 'hit-to-kill' weapons; they have fusing which detonates them when they get near their targets, so as to increase their chances of a hit. Given that, it is highly unlikely that a radar-guided SAM could produce an explosion 'within the airframe' of the airplane. Finally, such missiles are larger and more complex, and would be even more likely to leave large identifiable bits of themselves lying about. Finally, radar-guided SAMS need a radar! At this point, you'd need a ship or another aircraft equipped with tracking and guidance radar which guided the missile to Flight 800. This would mean that those firing the missile expected to see a large jet aircraft in their sights; especially given the location, this is not likely (unless, of course, they were ordered to shoot down TWA 800 specifically!)

It may be more fun to believe that there are deeper events than those we can see. However, in this case, positing a missile as the cause of TWA 800's demise introduces far more questions (and requires many more assumptions) than the official reasoning.