With many airlines now having a festive sale, it's a good time to remember to be careful checking flight prices. There is no longer a good flight comparison site, so it's time to do some research before you part with your cash.

Ryanair are advertising many fares free until 5th January, and if you can pick up one of these it's unlikely that you'll find any better deal. Remember that the flight is not actually free; you have to add in taxes, fees and surcharges to get the final price.

Advertising guidlines state that where offers are advertised as "from" an amount, that at least 10% of the seats should be available at the promotional rate.

We have a quick look at how this offer stacks up a busy domestic route - London to Glasgow.

Five airlines fly daily from London to Glasgow. We tried booking a variety of dates during February 2006 and found the lowest available return fare from Ryanair at £27.68 inclusive with British Airways offering £68.20 as its best fare.

All quotations were obtained direct from the airlines own websites.

Ryanair

Flying from London Stansted to Prestwick brings a total fare of £27.68, the lowest we could find by £8.30. Prestwick is around 30 miles outside Glasgow, but has a direct rail connection and good transport links.

Easyjet

Easyjet fly from Luton and Stansted to Glasgow International, around 11 miles to the west of the City Centre. The lowest flight we found was £35.98. Easyjet prices its fares on a one way basis, so you can fly out from Luton and return to Stansted to take advantage of a better fare if this suited you.

Flyglobespan

Flyglobespan fly from Glasgow International to Stansted. They offer a lesser flight frequency than the other carriers but despite this we easily found a lowest fare of £29.98.

BMI and British Airways

Being the two traditional carriers operating this route, both airlines offer a variety of ticketing options and business as well as economy service. Both fly from Heathrow, with British Airways also offering flights to Gatwick. As with Easyjet you can mix the two London airports if this suits you.

BMI offer a fare of £56.20 inclusive for the route, with the lowest we could find on BA of £68.20.

Differences Explained

Easyjet, Flyglobespan and Ryanair are all low cost carriers. Ryanair's flight costs £8.30 less than Easyjet but lands you at Glasgow Prestwick rather than Glasgow International. Other airlines may point out that Prestwick is further from Glasgow City Centre than Glasgow International, but whether this bothers you depends on your final destination.

BMI and British Airways are traditional carriers, although BMI no longer offers refreshments to economy class passengers on this route. Taxes and charges are both high for these carriers at £46.20, a significant part of which is a fuel surcharge due to rising oil prices. They are, however, the only carriers that offer flights from Heathrow which may make them attractive if you have an onward connecting flight.

Best Advice

Who offers you the best deal will come down to your individual circumstances, including which airport you prefer and the time of day you wish to travel. Generally the more flexible you can be, the better deal you will get. We recommend when booking flights you check the websites for the low cost, traditional carriers and at least one agent (such as Expedia or eBookers) before making your final decision.

Remember not to get taken in by the promotions and to always check total prices including taxes and charges before you buy.

Related Internet Sites

Airlines

BMI
British Airways
EasyJet
Flyglobespan
Ryanair

Travel Agents

Ebookers
Expedia