The 802.11ac-equipped AirPort card is removed with ease.

A comparison between the AirPort/Bluetooth cards from the MacBook Air 11" Mid 2012 (above) and the MacBook Air 11" Mid 2013 (below).

The AirPort card comes equipped with exactly the same hardware as we found in the 13" Air:

Broadcom BCM4360 5G WiFi 3-stream 802.11ac gigabit transceiver

Broadcom BCM20702 Single-Chip Bluetooth 4.0 HCI solution with Bluetooth Low Energy (BLE)

Skyworks SE5516 dual-band 802.11 a/b/g/n/ac WLAN front-end module