I was stationed at Diego Garcia from 2003-2005. I was the Air Traffic Control Branch Chief and I know the airfield there like I know my own living room.
This story is so full of holes that debunking it should be childs play for the least capable debunker (that would be me).
In order for this CT to work you would have to land a 777-200ER on a single runway without calling attention to it. Civilian aircraft are not a common sight on Diego. They do happen but when they do it is only from one contractor. This is a military airport and civil flights do not go there.
So let's say somehow they managed to land a 777 without anyone noticing it; where are they going to hide the aircraft? There are a grand total of 4 hangars on the island. These hangars are temporary enclosures for the B-2 bomber. They are tents that are barely larger than the B-2 and the B-2 is much smaller than a 777-200ER.
The length of a B-2 is 69 feet long, the 777-200ER is 209 feet in length. The B-2 has a 172 foot wingspan while the 777-200ER has a 199.9 foot wingspan.
Here is a picture of a B-2 in the enclosure at Diego Garcia:
As you can see there is barely enough room for the B-2 to fit in one of the four temporary hangars on the island. No way you can put a 777 of any variety in there and hide it.
The CT folk would say, "It is a military base, you don't have to hide it." Diego Garcia has literally thousands of Filipino and Mauritius natives who work on the island. You would have to hide it from them, as well as the merchant marines that are constantly in the lagoon and the civilians who run the Seamans club.
But the most important point is this: With no cellular service on the island just how did he send his text?
I have seen the CT's argue that there is Cellular service on the island. Wish I had known that when I was using walkie talkies to run the airfield. We were able to use sat phones on rare occasions. If there were cellular service of any kind the military would make sure we were using that instead of the much more expensive sat phones.
The CTs will point to internet searches for Cell service show Diego Garcia. Yes, if you do a google search for Diego Garcia and Cell phone a host of people want to sell you service! But once you actually spend some time looking into it further you will find that NOBODY offers either incoming or outgoing cell service.
Here is what the welcome aboard package each new sailor receives before coming to the island says about telephone service:
The commercial/private phone system is operated by Cable & Wireless, the local British phone company. Phone cards must be purchased to call off the island. Stateside phone cards will not work. Phone cards come in increments of $10, $20, $50 and $100 and may be purchased at Cable & Wireless. When your card gets low you can have it updated at the C&W office. Phone calls range from 40 to 60 cents a minute depending on time of day. If you have a computer, bring it along. Another way to keep in touch with the folks back home is e-mail, Instant Messenger, or webcam. Private Internet access is available through C&W for a one-time $20 fee and at a cost of 2 cents a minute from 0001-0449 and 4 cents per minute from 0600-2400 for a dial-up connection. A private DSL internet connection is available for $95.00/month. There are also Internet Café computers free of charge at several locations for personal use. Do you want to send a card or letter home by mail? Diego Garcia is home to the only U.S. Post Office in the Indian Ocean. The average time for mail to and from the States is about 8-10 days. Regular letters up to 13 ounces can be mailed for free.
While the company's name is Cable & Wireless there is no Wireless on the island.
Last but not least - There is no place on the island to put nearly 300 captives. The British police on the island have a single cell that is used more often than not for British Marines to sober up. There would be no place to put them.
The Air Force has to live in tents on the island.
This is possibly one of the worst CTs I have ever seen and easy to debunk... Hell if a 56 year old fart like me can do it.