although there may be other resident pilots and aviation buffs.

Fuel tanks do sometimes explode. It's rare (thankfully) but it does happen from time to time. For example, I remember an Air Force KC-10 that exploded on the ground several years ago. There was also a Boeing 737 explosion in Asia this year.

http://www.avweb.com/newswire/news9944a.html
http://seattlep-i.nwsource.com/business/tank03.shtml

There are a lot of people who believe the TWA 800 crash or the cause is the result of some conspiracy. They seem to want to believe this even through the physical evidence (and common sense) doesn't support their idea. Perhaps those who're drawn to wanting this to be the result of some big conspiracy are the same who believe in other big conspiracies, such as alien artifacts on the moon or the Face on Mars or UFOs. If they can convince people that TWA 800 was the result of a government conspiracy or coverup, then why couldn't all of their other pet conspiracies also be true? Once you go down the path of believing in big government conspiracies, then one is just as good as another. Of course, some paths lead to madness. Having worked in and with the government for some time now, I frankly don't believe it's competent enough to order lunch much less keep some monstrous secret for years.