Computersight -

1.  Choice in size

The MacBook Air comes in a 13″ model and there are no larger screen sizes.  However, the MacBook Pro comes in 13″, 15″ and 17″.  This gives the buyer more of an option in screen size.

2.  Ports

The MacBook Air has only one USB port.  No firewire or ethernet.  Of course you could purchase a USB hub but that would make the computer a lot less portable.  The MacBook Pro has multi USB ports, firewire ports and an ethernet port built in.  

3.  CD/DVD drive

The MacBook Air does not come with a CD/DVD drive.  To use a CD or DVD you will either need to plug an external one in, thus making it less portable.  Or use the CD/DVD drive of another Mac or PC wirelessly.  And again, the MacBook Pro comes with one built in.  Easy ah?

4.  Speakers!

The MacBook Air, although coming with iTunes, does not have any speakers!  To listen to music, you will either have to use headphones or external speakers.  The MacBook Pro comes with one decent speaker on each side of the computer.  That is, again another thing the MacBook Pro has that is built in.

5.  Hard Drive Size

The MacBook Air has a smaller and slower hard drive than the MacBook Pro.  You will notice this when trying to do multitasking on the MacBook Air.  The MacBook Pro has a more powerful hard drive.