One of the other things I like to work with is transportation. The old "Useful Stuff" page had a lot of airline links. I also have some ground transport links, as well as a few things for shipping. While I haven't actually flown all the airlines I list here, I have used all the intracity systems, as well as Amtrak and the Washington Ferries.
Airports | Planes | Trains | Automobiles | Boats | Intracity Rides | Shipping

Airline Flight Information
• United Airlines
• American Airlines
• Delta Airlines
• Southwest Airlines
• Northwest Airlines
• USAirways
• Continental Airlines
• Alaska Airlines
• Air Canada
• British Airways
• Air France
• Qantas Airways

Airport Information: CODE - City (Airport name) -- Administrative Agency
• ATL - Atlanta (Hartsfield Atlanta International) -- City of Atlanta Department of Aviation
• BIL - Billings (Logan International) -- City of Billings Aviation and Transit Department
• BLV - Mascoutah (Midamerica) -- County of St. Clair
• BOS - Boston (Logan International) -- Massachusetts Port Authority
• BUF - Buffalo (Buffalo Niagara International) -- Niagara Frontier Transportation Authority
• BWI - Baltimore (Baltimore-Washington International) -- Maryland Aviation Administration
• COS - Colorado Springs -- City of Colorado Springs
• DAL - Dallas (Love) -- City of Dallas Department of Aviation
• DCA - Washington (Ronald Reagan National) -- Metropolitan Washington Airports Authority
• DFW - Dallas-Fort Worth (International) -- Dallas/Fort Worth International Airport Board
• DIA - Denver (International) -- City & County of Denver Department of Aviation
• DTW - Detroit (Metro) -- Wayne County Department of Airports
• ERI - Erie (International -- Tom Ridge Field) -- Erie Municipal Airport Authority
• EWR - Newark (International) -- Port Authority of New York and New Jersey
• HOU - Houston (William P. Hobby) -- Houston Airport System
• HNL - Honolulu (International) -- Airports Division, Hawaii Department of Transportation
• IAD - Washington (Dulles International) -- Metropolitan Washington Airports Authority
• IAH - Houston (George Bush Intercontinental) -- Houston Airport System
• JFK - New York (John F. Kennedy International) -- Port Authority of New York and New Jersey
• LAS - Las Vegas (McCarran International) -- Clark County Department of Aviation
• LAX - Los Angeles (International) -- City of Los Angeles Department of Airports
• LGA - New York (LaGuardia) -- Port Authority of New York and New Jersey
• MDW - Chicago (Midway) -- City of Chicago Department of Aviation
• MHT - Manchester -- City of Manchester Airport Authority
• OAK - Oakland (International) -- Port of Oakland
• ONT - Ontario (International) -- City of Los Angeles Department of Airports
• ORD - Chicago (O'Hare International) -- City of Chicago Department of Aviation
• PHL - Philadelphia (International) -- City of Philadelphia Department of Commerce Division of Aviation
• PIT - Pittsburgh (International) -- Allegheny County Airport Authority
• PMD - Palmdale -- City of Los Angeles Department of Airports
• PNE - Philadelphia (Northeast Philadelphia) -- City of Philadelphia Department of Commerce Division of Aviation
• SBA - Santa Barbara -- City of Santa Barbara Airport Department
• SEA - Seattle (Seattle-Tacoma International) -- Port of Seattle
• SFO - San Francisco (International) -- Airport Commission of City of San Francisco
• SJC - San José (International) -- Airport Commission of City of San José
• STL - St. Louis (Lambert-St. Louis International) -- St. Louis Airport Department
• VNY - Van Nuys -- City of Los Angeles Department of Airports
• YUL - Montréal (Dorval International)

Intercity Rail Information
• Amtrak

Intercity Driving Information
• Illinois Department of Transportation Road Information

Boat Information
• Washington State Ferries

Intracity Transit Information
• Chicago Transit Authority (bus and subway/el in Chicago, Illinois)
• Metra (suburban commuter rail in Chicago, Illinois)
• Pace (suburban bus in Chicago, Illinois)
• Champaign-Urbana Mass Transit District (bus in Champaign and Urbana, Illinois)
• King County Metro Transit (bus in Seattle, Washington)
• Washington Metropolitan Area Transit Authority (bus and subway in Washington, DC, and surrounding areas)
• Southeastern Pennsylvania Transportation Authority (bus, subway, and commuter rail in Philadelphia, Pennsylvania)
• NJ Transit (bus and commuter rail throughout New Jersey)
• Port Authority Trans-Hudson (subway service between Newark and Hoboken, NJ, and New York, NY)
• Metropolitan Transportation Authority (bus and subway in New York, New York, plus LIRR rail)
• CAT (Citizens Area Transit) (bus in Las Vegas, Nevada)
• Metropolitan Transportation Authority (bus and light rail in Los Angeles, California)
• la Société de transport de la Communauté urbaine de Montréal (bus and subway in Montréal, Québec)

Shipping Information
• United States Postal Service ZIP+4 Lookup
• United Parcel Service Time-In-Transit Calculator