Wireless eavesdropping captures Wi-Fi traffic passively — on open networks, all traffic is readable. WEP is trivially decrypted. WPA2-PSK traffic can be decrypted if the handshake is captured and the PSK cracked.
WPA2-Enterprise (802.1X) protects against passive eavesdropping — even if other clients' traffic is captured, it can't be decrypted without their unique key. Always use WPA2/3-Enterprise for corporate Wi-Fi. Use VPN even on corporate Wi-Fi for sensitive work.