The MacBook Air Early 2015 has an 802.11n WiFi standard which is better than most portable PCs of a comparable age and spec to it. Most MacBooks that are a similar age to it have an 802.11a WiFi standard. In addition, this notebook PC have 802.11ac and 802.11b and 802.11g WiFi standards.
This notebook PC's Wi-Fi standard (802.11n) is actually the best Wi-Fi standard across all portable PCs of a similar type and age to the MacBook Air Early 2015.
The worst Wi-Fi standard across comparable types of notebook PC is 802.11a.