I've had a MacBook Air, actually I still do, my wife uses it.
My 13" MBP is no problem to carry compared to the Air. It's a full featured laptop easy to take anywhere no worries about battery life, ports, heat or fans blaring ...
I love my 13" MBP, my 15" rarely gets used for more than a desktop in my home office, otherwise the 13" comes with me everywhere.
It will take a hell of a MacBook Air upgrade for me to switch back ... the 13" MBP has a better keyboard, screen more ports, dvd player although I could do without that, most of all it's quite powerful with a 256ssd and 8gb ram ... it does everything I need it to do including heavy lifting, I don't even notice a huge speed difference from it to my 15" MBP or my Mac Pro....
13" MBP is great!!! You'll be hard pressed to find a better 13" notebook on the market right now.