Diego Garcia is a large American naval ship and submarine support base, military air base, communications and space-tracking facility, and an anchorage for pre-positioned military supplies for regional operations aboard Military Sealift Command ships in the lagoon.
If you take a look at the map below, you’ll notice the length of the runway is about 3000 meters, which is sufficient for a Boing 777 airliner to land and take off. The Captain on Flight 370 had actually practiced landing at the Diego Garcia air base on his flight simulator, investigations revealed.
CIA map of Diego Garcia (click to enlarge)
Against the Grain 
MH 370 probably landed, unloaded, refueled, and flew off to a remote, secure location for refitting for a false flag use…or flown into the southern Indian Ocean to complete the hijacking by an electronic warfare AWACs.
Could very well be. But this retired general might also have a valid point.