The current kernel of Fedora 21 doesn't support the Wifi chip used on my Mac Book Pro. Proprietary Broadcom drivers are packaged and available in the rpmfusion repo.
Verify that your card is a Broadcom using: lspci -vnn -d 14e4:
Sample output:
02:00.0 Network controller [0280]: Broadcom Corporation BCM4360 802.11ac Wireless Network Adapter [14e4:43a0] (rev 03)