Diego Garcia is not the issue here. There are many military bases around the world that are accessible to the U.S. and Britain. As far as the U.S. having enough bombers to destroy 10,000 targets in a few hours, they do, they don't need Nato! Your the one in the realm of fantasy here.
UN to hold off on separate Afghan bombing probe for now (Reuters)
from the article: Report: U.S. positioning 'bunker-busters' for possible Iran strike