Transport

Airports on Stamps & Postal Stationery
Stamps and postal stationery items that feature the theme of "Airports".
http://www.freewebs.com/airportstamps/index.htm

Astronomy and Cosmology in Stamps
Travel the world of Astronomy and Cosmology on stamps
http://ircamera.as.arizona.edu/NatSci102/images/extstamps.htm

Audi Philately
Stamps on Audis
http://www.freewebs.com/audiphilately/

Aviation and Space Postal Stamps
Aviation, aircraft, helicopters, pilots, air&space, history of aviation, etc., on stamps.
http://www.geocities.com/davor2405/philately.html

Balloon in Philately
Ballooning in Philately - Balloon Mail, Balloonpost.
http://www.wydera.de/balloon/index.html

Ballooning Stamps of the world
A collection of world balloon stamps.
http://www.ballonpostzegels.nl/Engels/ind_eng.html

Bicycles on Stamps
Page of Bicycle Stamps and Cycling Events.
http://www.poepperl.de/

Citroen stamps
A Citroen stamp collectors site.Indexed by country and model
http://www.philatecit.org

Hindenburg Crash Mail - the Scout Covers
Salvaged mail from the Hindenburg
http://www.slettebo.no/scout/hindenburg.htm

Indian Railways in Postal Stamps
A collection of images of stamps pertaining to railways in India along with notes and technical details
http://www.irfca.org/articles/vikas/stamps.html

Norwegian Railways in Philately
A presentation of postage stamps, postmarks and postal stationeries related to Norwegian railways issued in Norway and abroad.
http://home.online.no/~jdigrane/norway/stamps_0.htm

The Pan Am Flying Boat Service - Stamps & covers
 Stamps and covers produced for the first Pan American flying boat service across the Pacific
http://marshall.csu.edu.au/Wake/Stamps/PanAm_Stamps.html

Railway Stamps
Major specialty train stamps.
http://www3.mistral.co.uk/paper.heritage/railways.html

Railway Thematic Stamps
Railway topic in stamp collecting.
http://www.uqp.de/stamps/

Ships on Stamps Gallery
A collection of stamps on Ships.
http://www.stampship.com/

Ships on Stamps Unit
Ships on Stamps Unit-American Topical Association-American Philatelic Society-Dedicated to the study of philatelic material pertaining to watercraft on stamps
http://www.shipsonstamps.org/

Submarine's Covers and Stamps
Ronny Saxe's Submarine Covers and Stamps.
http://users.skynet.be/RonSubCovers/Postzegels/ZegelsIndex1.htm

Trains on Postal Stationery
A collection of rail related world wide postal stationery with images and write up.
http://www.alphabetilately.com/TOPS.html

Trains on US Stamps
U.S. postage stamps and postal stationery with a train or rail theme, as listed in Norm Wright, Sr.'s ATA Handbook 138, World Railways Philatelic. The stamps are arranged by types
http://alphabetilately.com/US-trains.html

ZeppelinPost
Site dedicated to Graf Zeppelin who started the glorious era of Postal Services via the flying Zeppelin.
http://www.zeppelinpost.20fr.com