Dude, here's the straight shibby: do whatever internship you want, regardless of whether it will help your career or not. I did an internship with the AOPA Air Safety Foundation the summer after I graduated. Did it quicken my journey to a jet? No, but I had an absolute blast doing it.
Seriously, if it looks like fun to you, go ahead and do it. Intern with freakin' Disney if you want to. There's no way of knowing, right now, if an internship will help you two years down the road. The airline might not even EXIST when you're ready to apply!