Fly into Humberto Delgado Airport (LIS), the closest airport, located 7.1 mi (11.5 km) from the city center. If you can't find a flight that works for your travel itinerary, you can also fly into Cascais (CAT), which is 6.7 mi (10.8 km) away.
Consider catching the metro at Algés Stop or Algés - Pç. D. Manuel I Stop to see more of the city.