Get a Pro. Air's are for *******.
lol, but no, trust me, the Pro is still a better all around computer. Air's are a nice novelty, but they're too limited, you can't upgrade as many components as you can in your pro.
MBA runs on flash memory so it accesses files faster, but doesn't have as much capacity,with the baseline you get 64GBs with a max of 256 GBs, while the MBP has a 320 GB Hard drive baseline, and is upgradeable to 750 GBs.
Both have 4 gigs of RAM, you can upgrade to 8 on the MBP though, but the Air maxes out at 4 GB.
You can get up to a 2.3 gHz i7 processor on the Pro, while the air maxes out at a 1.8 ghz i7
with the bigger pros (15" and 17") you get 2 graphics cards, the Intel HD and the AMD HD, while the Air and 13" MBP only have the Intel HD card
The Pro has a firewire port, the air does not
The air has Bluetooth 4.0, while the Pro has Bluetooth 2.0
The Pro comes with Snow Leopard installed for now, and the Air comes with Lion already installed. (as if that really matters)
The Pro has a Facetime HD webcam, while the Air just has a normal facetime camera.
http://www.apple.com/why-mac/compare/
To make it simple, the Air is a lot more limited than the Macbook Pro. The Pro can always be upgraded with more ram and a bigger harddrive as time goes on. But if you get the air, the upgradeable components aren't as plentiful, but it is much lighter, cheaper, and somewhat snappier than the MBP especially because of the flash memory.