Why is the AirPcap USB wireless capture adaptor not shown in the capture menu?
Wireshark version 3.0.1 - 64 bits AirPcap Adaptor: setup_airpcap_4_1_3, on AirPcap NX
On Windows 7 Enterprise
Please provide Help -> About Wireshark details.
My guess is that you've installed npcap instead of winpcap, but not in winpcap-compatibility mode.
I have Npcap 0.922, and WinPcap (internal version 5.0.992.323) installed