I visited this site:
And, selected the last option:
Select a letter for ICAO Codes: and chose "B"
I assume that you have permission from the website to use their database and that you are allowed to scrape their website. In any other case, it may be illegal to do this, depending on jurisdiction.
The problem here is that you are using GET to retrieve the contents, but the website is expecting a POST. Get and POST are not equivalent, although some programmers consider them the same (in PHP, for example, you can use
$_REQUEST instead of
$_POST). This website is not like them, so you have to POST to this website.
In Python, you can post data to an url like this:
import urllib2 u = urllib2.urlopen("http://www.avcodes.co.uk/airllistres.asp", "statuslst=Y&iataairllst=&icaoairllst=B&B1=Submit") print u.read()