good searches or good traffic?
i think your idea is the best bet
as most who book travel online, use drop downs to choose flights and destinations.
airports are typically within those descriptions, so how many are actually typing the term (chicagoairport) when considering travel plans?
develop as info site on the two main airports here in Chicago, then expand on those smaller, regional airports that exists outside of city limits.
include which airlines cater to which airports, types of planes, vendors, food services, public/private transportation to and from, etc...
maybe join some travel affiliates, and if you get good placement with kw, hopefully you'll generate some booking comp.
as is $300 > $1200
imo...
Good Luck!