Exactly. Airborne nukes are outdated. Landbased missile silos are still in use in the east-west Europe context as it's a contiguous land mass of more than ten thousand miles from the English Channel (western end of France) to the Bering Straits (eastern end of Russia). Why send the nuke by air mail it can be sent by e-mail? For the rest of the world, US, Russia, UK and France can nuke anywhere they like with ballistic missile launched from submarines, and nobody knows where these submarines are lurking with 70% of the earth being ocean.