Airports and flight route data, aggregated and sliced in various ways.

Sources:

OpenFlights 
(all tables except "cities to cities in time")
http://openflights.org/data.html

Research and Innovative Technology Administration (RITA)
("cities to cities in time" table)
http://www.transtats.bts.gov/DL_SelectFields.asp?Table_ID=260

Tables:

• countries to countries (current active routes)
  table (csv)
  [ country departure name | country arrival name | number of routes ]
  aprox. dimensions 3×4600
   
• countries to countries (current active routes)
  network format (gml)
  ~230 nodes, 4600 edges
   
• cities to cities (current active routes)
  table (csv)
  [ city departure name | country departure name | long. departure (decimal) | lat. departure (decimal) | city arrival name | country arrival name | long. arrival (decimal) | lat. arrival (decimal) | number of routes | distances (km.) ]
  aprox. dimensions 5×30000
   
• all routes (current active routes)
  table (csv)
  [ airport departure | city departure | country departure | long. departure (decimal) | lat. departure (decimal) | airport arrival | city arrival | long. arrival (decimal) | lat. arrival (decimal) | airline name | airline country based | route ID | number of stops | distances (km.) | domestic ]
  aprox. dimensions 12×58000
   
• cities (current active routes)
  table (csv)
  [ city name | country name | most active airport | long. airport | lat. airport | number of routes | number of incoming flights | number of outcoming flights | number of incoming domestic | number of outcoming domestic | number of incoming international | number of outcoming international | average distance (km.) | max distance (km.) ]
  aprox. dimensions 14×3000
   
• cities to cities in time (1990-2010)
  ONLY FLIGHTS INCLUDING A U.S. CITY AND A NON-U.S. CITY (due to different data source)
  table (csv)
  [ departure city name | arriving city name | number passengers 1990 | number passengers 1995 | number passengers 2000 | number passengers 2005 | number passengers 2010 ]
  aprox. dimensions 7×12000