Ngaire, I see the following:
AIRPORT HOTELS
There are no hotels at the airport. Nearby hotels include the Radisson SAS Hotel Lisboa, the Holiday Inn Lisbon, Marriott Lisbon and the Holiday Inn Continental.
I'm not sure when you're going or if you took advantage of the free night's stay (and 15,000 points) when you apply for a Marriott Visa card but the Marriott in Lisbon is a Category 4 hotel so you could stay for free if you go by June 30,2006.
