I just got a 15" Mac Air. I'm trying to move the info on my old MacBook Pro to the new computer.

There are actually three means of migrating from an old MacBook to a new one:

• From a Time Machine backup external disk.
• Over WiFi (both computers must be on the same WiFi network).
• Direct cable connection. This is the fastest means. Adaptors are available if you don't have a USB C to USB A adaptor. If your old MacBook has Thunderbolt ports, all you need is a Thunderbolt -> Thunderbolt cable. I picked up an Apple cable at Amazon, and got it the next day.

Here's the Apple Support article on Migration Assistant: Transfer to a new Mac with Migration Assistant - Apple Support

After you've completed the migration, don't forget to prepare your old Mac for sale or trade-in. There's a link at the bottom of the above article on what you need to do.

Hope this helps.

I strongly recommend against Wi-Fi. it is usually to slow for this amount of data and often results in corrupted data. Get a USB cable with the right connecters or get an adapter. They are easily available for a reasonable cost at many stores or on-line. Then use the Migration Assistant app and follow the instructions and all should go well.

I've never used the WiFi method, and up until last month had always used the Time Machine backup method, which took hours to complete.

Last month I used the direct Thunderbolt <-> Thunderbolt connection, and all my data was transferred within 40 minutes.

An external disk containing a bootable clone backup of the old system (e.g., a backup made with Carbon Copy Cloner or SuperDuper!) will also do.