2London2
Find out which budget airlines operate from London's airports and where they fly to, with the aid of 2London2.
https://www.2london2.com/

411sync
SMS text-based fare search service.
http://411sync.com/cgi-bin/travel.cgi#anchor23

A2B Travel
Use the "Fare Finder" facility to bag a bargain.
http://www.a2btravel.com/bestbuys/farefinder.asp?source=topnav

Airfare Watchdog
Uses real people to search for the lowest fares each day.
http://www.airfarewatchdog.com/

Airfares Flights.com
Rudimentary flight comparison engine for flights departing from the Australian continent.
http://www.airfaresflights.com.au/

Airflights Direct Ltd
Search from a huge online database of charter flights, scheduled flights and bargain holidays.
http://www.airflights.co.uk/

All Check In
Savvy travellers can use this comparison site, which covers 500 airlines, over 80,000 hotels and a handful of car hire firms, to find the best deal and save money.
http://www.allcheckin.com/

Applefares.com
Find the lowest fare on the following airlines: Air 2000, AirBerlin, Air Scotland, BasiqAir, BMI, bmibaby, easyJet, GermanWings, Globespan, Hapag-Lloyd Express, Jet2, MyTravelLite, Sky Europe, SkyNet Airlines, Sterling, Thomsonfly, V Bird, Virgin Express and Volare.
http://www.applefares.com/

Booking Buddy.com
Independent comparison site where you can compare the best flight, car and hotel deals before booking.
http://www.bookingbuddy.com/

Charter Flights.co.uk
Search 100 suppliers from this one site to find the best charter flight deal.
http://www.charterflights.co.uk/

Cheap Flights.ca
Lets you search for scheduled and charter flights, as well as lots of other travel deals.
http://www.cheapflights.ca/

Cheap Flights.com
Search for cheap flights from agents, airlines and specialists.
http://www.cheapflights.com/

Cheap Flights.co.uk
Well known guide to cheap flights, sales and specials.
http://www.cheapflights.co.uk/

Destina.ca
Compare airlines, hotels and car hire firms for the best deals.
http://www.destina.ca/

Ding
A free application from Southwest Airlines that instantly alerts you to special offers from the airline.
http://www.southwest.com/ding/

Discount Airfares & Airlines Compared
Independant price comparison site for airfares. You can also compare airlines on the basis of quality, safety, comfort, reliability, seat pitch and width.
http://travel.simplyquick.com/discount-airfares/

Dohop.com
Lets you search for the cheapest or the most convenient flight by filtering results by airline, aircraft, airport, flight time or the number of stops.
http://www.dohop.com/

Entravelment.com.au
An independent travel comparison website that searches Australian travel agent websites to bring you the best deals to destinations worldwide.
http://www.entravelment.com.au/

ETN Telephone.com
Use this table and a bit of math to work out how good a deal you really got on your discounted airfare.
http://www.etntelephone.com/goodbad.htm

Expedia.com
The "fare compare" service shows the best prices recently found by Expedia's US customers on a given route.
http://www.expedia.com/flights/

ExpertFlyer
Not a comparison site, but a subscription service that offers air travellers unbiased advice on which flights to book, how much to pay and which seat to choose, as well as tips on fare rules and restrictions, maximising frequent flyer miles and securing upgrades.
http://www.expertflyer.com/

FAQs.org
General links and information about airfare tracking websites.
http://www.faqs.org/faqs/travel/air/online-info/

Fare Catcher
Never miss out on a bargain fare again! This clever piece of software utilizes web-based travel services, like Internet Travel Network, to periodically go online and obtain the lowest fare prices for specific trips that you define. It's not free though, as you are expected to make a donation to the Autism Society of America.
http://www.spitting-image.com/products/farecatcher/

Fare Chase
FareChaser is a web-based fare search and booking solution that allows consumers to comparison shop for travel from over 150 different sites.
http://www.farechase.com/

Fare Compare
If you are flying to any destination to or from North America, then you can use this website to mine historical fare data on over 77,000 city pairs and find out the lowest ticket price other passengers have paid recently.
http://www.farecompare.com/

Fare Measure
Pick an airport in the "Flights by Airport" section of this website and you get a rundown of which flights go in and out, along with an indication of what other travelers paid for those flights.
http://www.faremeasure.com/

Fare Report.com
This tool helps consumers find the lowest fare in the top 6,000 city pair markets in the US. Data comes from the Department of Transportation and includes fare info for over 30 major airlines.
http://www.farereport.com/

Farecast
Buy tickets at the optimal time with the aid of this website, which predicts future rises in airfares through careful analysis of past trends.
http://www.farecast.com/

FareWatch
Compare more than 6,000 city pairs for average airfares and see who the market leader is.
http://www.gofox.com/flights/farewatch.php

Flight Comparison
Flight Comparison specializes in finding the cheapest scheduled flights offered by leading online travel agencies.
http://www.flightcomparison.co.uk/

Flight Mapping
Find out who flies where from the UK using this interactive map.
http://www.flightmapping.com/

Flightful.com
Find the cheapest European budget flights.
http://www.flightful.com/

Flights Direct.com
Search for charter flights from UK airports to Mediterranean destinations such as Greece, Malta, Portugal, Spain and Turkey.
http://www.flightsdirect.com/charter-flights/

Flitesite.co.uk
Not a price comparison site as such, but a useful research tool which you can use to compare information about the routes, airports, cities and offers promoted by low-cost carriers in Europe, North America, Asia and Oceania.
http://www.flitesite.co.uk/

Flyspy
Gives a graphical display of all the flights available on your chosen route, their departure times and the range of different fares available. Use the site to work out the most convenient time to fly or the cheapest.
http://www.flyspy.com/

Foundem
A real-time travel search engine that trawls airlines, hotels, car hire companies, travel agents and consolidators to bring you unbiased quotes for discount airfares, hotels and hire cars.
http://www.foundem.com/

Fresh Holidays
A comparison service that searches the websites of budget carriers and tour operators to bring you the best flight, hotel and package holiday deals.
http://www.freshholidays.com/

Gooflight.com
An airfare comparison tool that allows you to search for the best deal on 16 European low-cost carriers.
http://www.gooflight.com/

Henoo
Flight, hotel, car hire and package holiday comparison site aimed at customers in the UK and Ireland.
http://www.henoo.com/

Internet Airfares
Look-up the lowest air fares published each business day among the top 50 metros in the US and Canada.
http://www.air-fare.com/

ITA Software
Online air fare shopping engine. Just click on the option marked "Login as a Guest" to try it out.
http://matrix.itasoftware.com/cvg/dispatch/

Kayak.com
Allows you to search for travel deals from over 100 online travel sites in one fell swoop using your computer or mobile phone.
http://www.kayak.com/
http://kayakmobile.com/

Kayak.com
Pick a departure point, set a budget, and Kayak's search facility will seek out a list of international destinations that fit the bill, as well as details of what others paid for the same trip.
http://www.kayak.com/h/buzz/flights

Kayak.co.uk
Check fare trends or interrogate 100+ travel websites in real time using Kayak.
http://www.kayak.co.uk/

Kelkoo.co.uk
Click on the section marked "Travel" to compare prices for flights, hotels and package deals from a range of suppliers.
http://www.kelkoo.co.uk/

Low Cost Seats.co.uk
Compare charter flights with low-cost carriers.
http://www.lowcostseats.co.uk/
http://www.lowcosttravelgroup.com/

Mobissimo
Searches over 120 travel sites for the best fares.
http://travel.mobissimo.com/

Momondo
Search for flights from over 300 websites covering more than 600 airlines, particularly low-cost carriers.
http://www.momondo.com/

Money Saving Expert
Dig out the best fares on Ryanair, MyTravelLite, BMIBaby and Flybe using this clever little tool.
http://www.moneysavingexpert.com/flightchecker/

Money Saving Expert
The difference between flight-brokers and screenscrapers explained, along with advice on how to use the Internet tactically when searching for airfares.
http://www.moneysavingexpert.com/cgi-bin/viewnews.cgi?newsid1120211097,47143,

Netfares Online.com
Displays air fares from over 80 different airlines. For travel agents only.
http://www.netfaresonline.com/

NexTag
Provides multisite search for flights, hotels and car rental. Prices are only given in US Dollars.
http://travel.nextag.com/

One Time
Allows you to compare air fares and hotels at a handful of popular websites.
http://www.onetime.com/

OpenJet.com
Compare, combine and book low-cost tickets with a handful of low-cost airlines.
http://www.openjet.com/

Orbitz
The company's Flex Search facility allows you to search for the lowest fare by altering your dates of travel, but not your budget.
http://www.orbitz.com/App/ViewRoundTripSearch?searchMethod=fareCalendarSearch

Orbitz
Use the deal locator service of this US travel portal to specify your price and they will alert you when they find a match.
http://www.orbitz.com/dealdetector/

Pinpoint Travel
A new offering from AOL that allows you to interrogate over 500 airlines and 85,000 hotels worldwide to find the best travel deal.
http://www.pinpointtravel.com/

Preferred Traveler
Search for savings on flights to destinations worldwide.
https://www.preferredtraveller.com/

Price Bookers.co.uk
Allows you to search multiple travel sites for the best flight, hotel, car rental and holiday package deals.
http://www.pricebookers.com/

PriceRunner
This well known price comparison site can now help you find the cheapest flight by searching the most popular travel websites.
http://www.pricerunner.co.uk/Flights.jsp

Qixo
Looking for cheap airfares with the right flight times? QIXO searches more than 28 popular airfare sites and finds you the best prices and flight times.
http://www.qixo.com/

Reid Bramblett
A step-by-step guide to securing the best airfare, including tips on how to get the most out of fare comparison sites.
http://www.reidsguides.com/t_pl_search_engines.html

SideStep
Find bargain hotel, flight and car deals, compare Expedia, Travelocity and the others side-by-side, book your travel with brands you trust, and get extra frequent flyer miles and special offers, all with this 130Kb travel search tool.
http://www.sidestep.com/
http://uk.sidestep.com/air/

Sky Low.com
Use this site to find the lowest fares offered by low cost carriers around the globe or to see which routes they fly.
http://www.skylow.com/

Skyscanner.net
Search for the cheapest airfare with a host of European no frills airlines.
http://www.skyscanner.net/

Telegraph - Travel
An article comparing a handful of airfare price comparison sites popular with British travellers.
http://www.telegraph.co.uk/travel/main.jhtml?
xml=/travel/2004/05/22/etsavvy22.xml

Telegraph - Travel
Us the Fare Finder facility on this site to get an idea of what others have paid to fly a particular route.
http://www.telegraph.otc-uk.com/bestbuys/farefinder.asp

Trabber
Searches 22 travel sites to bring you the cheapest airfare. Currently available in Spanish, German and US versions.
http://www.trabber.com/
http://www.trabber.com/us/
http://www.trabber.com/es/
http://www.trabber.com/de/

Travel.co.uk
Package holiday, hotel and charter flight search engine aimed at British travellers.
http://www.travel.co.uk/

Travel Ally
The "Fareaware" tool on this website will show you the average lowest fare, and the lowest fare by month, for the past year. Simply compare today's lowest fare against the average to decide if you should buy today.
http://www.travelinsider.us/fareaware.html

Travel Fusion
Online journey planner tool that queries 400+ travel sites for the best flight, hotel and car hire deals.
http://www.travelfusion.com/

Travel Grove
Save time by using Travel Grove to search several websites for the cheapest airfare, hotel, car hire and cruise deals.
http://www.travelgrove.com/

Travel Jungle.com
Search up to 40 different travel websites for the best deals, including scheduled airlines, budget carriers, hotel chains and car hire firms.
http://www.traveljungle.com/
http://www.traveljungle.co.uk/

Travel Market.com
Search suppliers and travel agents to track down the best air travel, accommodation and car hire deals on the Web.
http://www.travelmarket.com/

Travel Republic.co.uk
Search up to 20 different tour operators for the best value charter flights from the UK to over 80 destinations worldwide.
http://www.travelrepublic.co.uk/

Travel Secrets
Contains a fare comparison tool that is aimed at American air travellers.
http://www.travelsecrets.com/consair_frameset.htm

Travel Select.com
An airfare search engine owned and operated by Lastminute.com.
http://www.travelselect.com/cgi-bin/newconcept/main.cgi

Travel Supermarket
Search over two dozen travel websites in one hit to find the best fare or sign up to receive a weekly email detailing the best flight deals.
http://www.travelsupermarket.com/
http://www.travelsupermarket.co.uk/

Travelocity.co.uk
Sign-up to Travelocity's Fare Watcher service, specify how much you want to pay for a ticket, and you will be alerted via email when a match is found.
http://www.travelocity.co.uk/uk/help_main/0,,TCYUK|HELP_FW,00.html

TripStalker
Free automated software that continuously checks fares on the Internet and alerts you when it finds one that matches your specifications.
http://www.tripstalker.com/

U Fly 4 Less
Download this flight search utility to bag those bargain airfares on European budget carriers.
http://www.ufly4less.com/

UK Net Guide
Use this site to search for, though not compare, fares on a clutch of major British travel sites.
http://sub.uknetguide.co.uk/Travel/Flight_Search/

Wegolo
A low-cost airline search and reservation engine that covers European 50 carriers.
http://www.wegolo.com/

WhichBudget.com
Cheap flights search engine that monitors both budget and charter airlines.
http://www.whichbudget.com/

Yahoo! FareChase
Yahoo! FareChase searches multiple travel service providers to find you the best flight, hotel and car hire deals.
http://farechase.yahoo.com/
http://www.farechase.com/

Yapta
Claim a refund or travel credit on your airline ticket, if its price drops after you've bought it, by using Yapta's handy price monitoring/flight tracking tool to alert you.
http://www.yapta.com/

Zuji
Asian and Australasian travellers can use Zuji to track down the lowest airfares to their preferred destinations.
http://www.zuji.com/