The MacBook Air Early 2015 has an 802.11n WiFi standard which is better than most laptops of this spec and age. Most MacBooks that were released around the same time as it have an 802.11a WiFi standard. In addition, this portable PC have 802.11ac and 802.11b and 802.11g WiFi standards.
This notebook PC's Wi-Fi standard (802.11n) is in fact the best Wi-Fi standard amongst all MacBooks that were released more than a year ago.
Amongst comparable types of notebook PC the worst Wi-Fi standard is 802.11a.