Willard Airport is probably one of the smallest airports (if not the smallest airport) I've ever flown in and out of.
The cons:
- it's only got one terminal.
- only three airlines fly there (or is it two?).
- the only destinations are Chicago, Dallas and Detroit.
- it's hard to get a taxi... usually you have to call for one.
- the weather is Illinois weather, which means that it sucks in the winter, and there are many flight cancellations and delays.
- the flights to and from Chicago are usually late (when they're not canceled), because ORD is so terrible.
- there's pretty much no food sold in the airport.
That sounds pretty dismal, but small airports also have their advantages:
- there is never a line to check in or to go through security.
- boarding is usually extremely efficient.
- parking is not an issue: there's barely any traffic, and long-term parking is only $5/day and is literally across from the terminal entrance.
- plenty of car rentals.
- it's only a 10 minute drive to downtown Champaign.
- because of all of the above, no need to get to the airport too long before your flight.
On top of that, there is free wireless if you're affiliated with the university (the airport is indeed operated by the university). 3-1/2 stars, considering the small size of the operation.