Good luck with that. You're correct in that securing an airway is THE issue. However, most people with these fractures are dead before EMS can even attempt an airway. That is a trait shared by many injuries (such as aortic separation) that have enormous mortality rates. And because these injuries are both rare and subtle, they're very commonly overlooked. By the time symptoms are clear, laryngeal fracture makes successful intubation extremely unlikely. Ditto cricothyrotomy. Tracheotomy is the best option, but I do not know of any EMS program in the US that teaches that procedure.
There's a good article on Medscape
HERE, from 2016. They do discuss various causes of these injuries, but given their rarity it's not surprising that there's no effort to break down statistics by etiology. The sample size for each would be too small to draw any meaningful conclusion.