HoDo, you've got to be fairly close to the airport to hear all the ground controllers which are necessary to really enjoy listening to this segment of communications. I'm within a couple of miles of BWI and hear everything with just the radio's whip antenna including even the trucks on the runways. As you move away from the airport more than a few miles, you'll need an outdoor antenna of some sort. Within about 10-15 miles you can still hear a portion of the controllers with an omni-directional antenna like a discone but the controllers that move traffic on the runways, taxiways, etc operate at lower power and are difficult to hear even with the outdoor antenna. Once you get beyond that zone you'll pretty much need a beam that covers the aircraft band of frequencies to hear much of anything from the ground. This is all very generalized of course and higher elevations make a big difference in listening ability.