Gents,
Be careful judging from the comfort of our current position; history is all about context - the airborne alert was there 24/7 for good reason so accidents were nearly inevitable. It wasn't just the US that were a little 'fast and loose' with such weapons in this period; google the 'Violet Club' interim megaton (ish) massive fission weapon deployed in small numbers by the RAF as an emergency weapon prior to deliveries of 'productionised' fusion weapons (such as YS). The lack of safety breaks in that weapon are hair raising to say the least......but it tells you a bit about the pressures of living in that nuclear shadow.