A recommendation is purely that....." I recommend that this guy is a good sh*t based my experience flying with him". A sponsor is someone that is willing to be "responsible" for you during your first year with the company. In other words, I can recommend a guy because I think he might be a good fit, based on what I've experienced with him in the cockpit/on my wing. I may have never had any beers with you, but based on what I know, you're a good stick. A sponsor is someone that knows you a bit more personally, and is willing to go to bat for you, and show you the ropes on how to operate/perform during your probationary period. If you step on your wiener during your first year, you AND your sponsor will be standing tall in front of your chief pilot explaining your "deficiencies.