If that was the real plane carrying a nuke enough to level Manhattan, wouldn't the nuke explode and destroy the base along with them if he fired a rocket launcher at it?
Detonating a modern nuclear device is, in fact, incredibly difficult and merely shooting down the aircraft carrying it would not be sufficient.
In fact, several aircraft carrying older nuclear devices have either crashed or otherwise been lost without the device on board detonating.
It's likely that the crash might cause a release of nuclear material but detonation is practically impossible.
...another B-52 carrying four hydrogen bombs crashed near the Spanish town of Palomares on Spain’s southeast coast after colliding with a refueling tanker. One of the four bombs was recovered virtually intact, according to The Washington Post, but two others released plutonium when their explosive triggers detonated. A fourth bomb fell into the sea, prompting a search that involved thousands of uniformed personnel, millions of dollars and 20 ships that ranged from submarines to minesweepers.
The fourth bomb was eventually recovered, but radiation released by the damaged weapons required a U.S.-led effort to decontaminate 640 acres of topsoil in the farmland around Palomares, Tad Sczulc reported in the Times. Military personnel initially wore face masks and gloves as they removed the soil, according to Sczulc’s account, and more than 1,600 tons of contaminated soil were sealed in steel drums and shipped to the U.S. for disposal.
In 1964, a B-52 carrying two unarmed atomic bombs crashed in western Maryland. In 1961, two nuclear-laden B-52s went down — one near Yuba City, Calif., and another north of Goldsboro, N.C. The bombs survived both crashes without detonating