Diego Garcia is in Indian Ocean, 2200 mi from Malaysia. The radar shows that MH370 went into the Indian Ocean not Pacific. If carrier was in the South China Sea, it would be pretty obvious that it was there and involved.

Carrier group is even less likely to shoot down airliner. In middle of ocean or crowded area like South China Sea, carrier group probably doesn't have its defenses on alert. It has fighters that can intercept and visually identify aircraft. In the middle of ocean, there is plenty of time to react. There isn't the hair trigger in middle of war zone that led to Iran Air Flight 655.

How far is the Indian Ocean from the west pacific?