Is it at all possible to capture Dot11 headers under Scapy in Windows? I'm thinking Winpcap, but I'm not sure how I'm supposed to do that. Any clues?
WinPcap does not have this ability, but its successor Npcap can capture raw 802.11 frames. When installing, select "Support raw 802.11 traffic (and monitor mode) for wireless adapters." There are more directions in the Npcap User's Guide, but they may not apply to Scapy.
When the network adapter is put into NetMon (monitor) mode, captured packets will have a Radiotap pseudo-header with any available information such as channel, timestamp, signal strength, etc. Not all wireless adapters support this mode; a preliminary list of adapters and their level of support is available on SecWiki.org.