scapy - http header list over wlan

Question

I'm trying to get a list of all http headers being visited on my wlan. The code I'm using is (not my own):

#!/usr/bin/env python
import sys
sys.path.append("/usr/local/lib/python2.7/site-packages")
import re
from scapy.all import *
import os
import urllib


conf.sniff_promisc=True

HOST_REGEX = "(?<=\r\nHost\: )([A-Za-z\.]){4,40}(?=\r\n)"

def print_host_header(pckt):
  if pckt:
    raw = pckt.getlayer(Raw)
    if raw:
      raw_pckt_data = raw.load
      host_results = re.search(HOST_REGEX, raw_pckt_data)
      if host_results:
        print "[*] Request to: "+str(host_results.group(0))
if __name__ == "__main__":
  if os.getuid()!=0:
    print "[!] Not running as root."
    exit(1)
  sniff(filter='tcp', prn=print_host_header, store=0)

When I run this I'm only getting sites visited on my laptop (the laptop running the code). Visiting sites with another laptop does not yield any results (on the same wlan). I thought it might be because my wireless card isn't in monitor mode but I put wlan0 (as mon0) in to monitor mode and it made no difference. Does anyone know why?