Denver International Airport – DEN – offers free WIFI throughout the Airport Terminal Complex. Although they ask you view a 30 second ad spot this is hardly unreasonable given the cost savings of about $10 over the pay for WIFI airport installations.
I flew out via BWI this morning and although I really enjoyed the city of Baltimore, I would have had a great impression if they provided ad supported WIFI at the Airport.
Joe Duck 
They could probably sell some adspace about Please Watch Your Luggage As You Make This Internet Connection. If the opening screen contains a stylized MAP of the airport shopping area showing Terminals, Restaurants, Smoking Lounges, Hotspots, BaggageClaim, Taxicabs, etc. they have a source of revenue right there.
And just think how much of a “halo effect” ANY advertiser would enjoy if a harried traveller can get a good internet connection when he really needs it.
Good points FG. Although it’s possible the paid wifi airports are making money, I think the “win win” here is to have ad supported access which is going to reach about 100x as many people (perhaps with a pay for no ads option).
In a venue like an unfamiliar airport I *like* to see advertising for local shops, restaurants, etc. In a two hour layover you have time to kill and little experience in the place, so ads arguably can direct you to things you’d probably want to consider doing anyway. Little harm in the ads also, so those who ignore them get free wifi, too.
Commercially the strongest combination is probably to have free Wifi at restaurant and bar with minimum purchase. If I had a place in a paid wifi airport like BWI I’d do that and then advertise it. I would be *very happy* to arrange my travel plans to eat at the free wifi place rather than pay the airport for that service.
Think of someone who is not on layover but has reached his destination. He might still want to go a bar, check his email, … and then do the ground transportation and hotel etc. stuff.
Most readers of the advertisements however would be in-transit and be interested in “useful” time killing stuff. The nearby restaurant with the free wifi rather than the very lengthy hike to the internet access kiosk that charges an arm and a leg and might not be working anyway! The airport shopping guide specific to his terminal? Or perhaps while he is at the bar/restaurant he could also see an ad for the duty-free store or Products of that State store. Good time killing stuff to do during a layover and a perfect advertising opportunity for the merchants. Seattle area coffee shops have the obligatory dog biscuits, water bowl and free internet access. Very few coffee shops now fail to offer the free internet access. Its not like that with airports though. Yet!