After nearly going to the wrong terminal, I had to learn the hard way that What Terminal is Spirit at Boston Logan. Logan might be confusing, particularly if you're rushing. Everything went nicely after I located the correct location. Spirit's boarding procedure was simple, and the security line wasn't too bad. You get what you paid for, even though the plane wasn't particularly comfy. I paid less than $100 for a last-minute reservation. Good option for low-cost flights out of Boston for short getaways.