But it is not clear that India or Pakistan have succeeded in weaponizing nuclear warheads for delivery by missile. However, a ballistic or cruise missile offers distinct advantages over aircraft as a means of delivering a nuclear weapon. Both ballistic and cruise missiles are more likely to penetrate air defences and more likely to hit their targets than manned aircraft. Ballistic missiles are many times faster than an aircraft, whilst many cruise missiles can fly at very low altitudes and actively evade ground-based defences. These factors make missiles more survivable than manned aircraft.
Missiles are also less expensive to maintain and operate than aircraft.
In the future, these benefits may provide sufficient impetus for rogue regimes to succeed in weaponizing missile warheads either through concerted autonomous development programs, or the acquisition or theft of warheads and warhead technology from the former Soviet Union or another supplier. There has also been much discussion of the nuclear suitcase bomb or other terrorist-delivered weapon. A terrorist group could try to purchase a nuclear weapon, as the Japanese Aum Shinrikyo cult apparently tried to do in Russia, or build a crude device on its own, which is less likely given the technological hurdles. A small, terrorist device could be used for blackmail purposes, sabotage, or to contaminate and cause chaos in a key target of a political adversary. Major civilian population centres may be targeted in order to force dispersal of population, achieve wholesale terror and destroy the political and economic infrastructure of a nation.