The Migration Assistant program included over the last few years with Mac OS X moves pretty muchpersonal information — user accounts, settings, keychain password, files, folders and programs — on the old computer over to the new one. As long as your programs are compatible with the newer version of Mac OS X, they should run fine, but you may want to look for any free software updates that may be available.
Checking the system requirements for your most-used programs before you do the transfer can help you plan for any new versions you may have to buy. Programs that will not run on the newer system are automatically moved to a folder labelled Incompatible Software. If you try to use a program in this folder, the Mac usually refuses to open it and presents a system alert advising you to go get a compatible version. To actually transfer the files, you can connect the two MacBook Air computers over a wireless network or with a cable connected to each machine’s ThunderBolt port (if both Airs have one). If you use an external USB drive running Apple’s Time Machine software to back up your computer, you can also transfer the datathe old computer to the new one with a USB drive.