With our kids, we used two different devices. One was just a long strip of cloth that you tie in a special way. The other was a more structured carrier with straps and buckles and all that good stuff. For both of them, the child faces toward the parent, so they would be rear-facing relative to the plane. And both have an option to fully support the head. The main purpose there is just to protect their neck while sleeping or during moderate activity, but it would offer at least some additional protection against neck injuries in a crash, rough landing, or during periods of turbulence.
Perhaps crush injuries are more likely with the baby strapped to you, but honestly I would be more worried about a parent holding their baby being more likely to drop them in the aisle during an evacuation, which would be more likely to endanger everyone behind them on the plane as well.