Originally Posted by texashoser

Here's your answer:

The science is pretty basic, as explained by Brian Manning, a flight attendant for Mesa Airlines. "When the seat is up, it is locked. When the seat is back, it's not locked. In the event of an emergency, an unlocked seat has more force during impact, and the thrusting forward of that seat can cause passenger injury."

The seats on Spirit are permanently locked into a reclined position.