[I had thought about posting this one in the ASB forum, but decided that many of the James Bond movies were realistic enough that it could be discussed here]
ASB:
Thunderball
Stolen nukes would be useless without the codes to arm them, which would not be on the plane (altho with enough time, maybe SPECTRE could take them apart and use the fissile material to build new bombs from scratch).
You only Live Twice
So many people would have to be involved in the construction and staffing of Blofeld's volcano lair, would be impossible to keep its existence secret from the authorities.
The Spy Who Loved Me
1) Practically, how does Stromberg go about recruiting a small army of henchmen willing to help kill billions of innocent people?
2) Not sure if codes needed to launch nukes from a captured sub, would be located on board.
Moonraker
1) Circa 1980, a private individual (Drax) is able to construct a space station larger than any in existence by 2008 in OTL. Such a project would cost hundreds of billions, unless he is somehow able to launch materials into orbit for only a tiny percentage of the cost per pound in OTL, despite the fact that he appears to be using ordinary 1970's-tech space shuttles with throwaway boosters.
2) Stealth technology doesn't work in space, so the space station would have been noticed.
3) It's impossible for a chemical agent to be lethal for only a single species (humans) but no others.
4) Drax's globes might have contained enough of the gas to kill millions, but not everyone on Earth.
Also, maybe not actually ASB (since Drax is craxy), but it makes no sense for Drax to locate his "ark" in space, when it could just be built underground for less than 1% of the cost.