What makes a shipment time critical
A shipment is time critical when it has a hard deadline and serious consequences if it misses. A part for an aircraft waiting on the ground, a device needed for a scheduled surgery, a component for a stopped production line, equipment for a live event or documents for a filing deadline all fall into this group. The item may be ordinary; the deadline is what makes it critical.
That changes how the shipment is planned. Instead of asking how quickly the item can move, the question becomes what has to happen, and when, for it to arrive on time with room to spare.
SameDayAir.com plans them this way, starting from the deadline and working back to the pickup.
