Moving iTunes library from ancient MBP to new MacBook Air

I'd like to move my iTunes library from my 2008 (!) MacBook Pro running El Cap (!!) to Music on a brand new MacBook Air. Lack of a big kludgy old USB port on the new Mac prevents using my big-enough external hard drive for the move. I tried copying my library to iCloud Drive (again, plenty of available room) but it either isn't uploading or is taking an eternity to get the job done. I have a lot of music on the old MBP ripped from old LPs and tapes, so just downloading my Music Store purchase history won't get the job done.