Can I use iCloud to download all of my music to my phone?

iCloud allows you to redownload music purchased from the iTunes store, but your music is not stored in your iCloud account. (It is simply redownloaded from the iTunes store again.) The only way to access your music ibrary, including music not purchased from the iTunes store, is to subscribe to iTunes Match. If you want your music on your phone to listen to on the plane, just sync it to your phone using iTunes.