Independent money-saving guide: which airlines fly where?

OK - you've heard of all of the above, but what do they mean and which is the best for a cheap flight?
Well, here's some history. Easyjet started flying 12 years ago. Back then in 1995 the only real attempt in the UK to offer 'low-cost' flights had been by Sir Freddie Laker with his Skytrain. The Skytrain was a great idea but 20 years ahead of its time, and unfortunately, it failed.
Easyjet as we know however did not. It was a huge success and it arguably paved the way for the boom in cheap air travel that continues today. In less than 15 years Easyjet has come from nowhere to become the third largest airline in the UK, (after Ryanair and BA), and the sixth largest in Europe -(by scheduled passengers carried in 2006).
Easyjet has been called a 'no-frills' airline, other airlines call themselves 'low cost', 'budget', 'scheduled', 'charter' or 'flag carriers'.
So what's the difference? And how does it affect you getting the cheapest flights? Well to be honest the differences are much less than they used to be -but here goes with an explanation.
Scheduled flights are flights operated by airlines that fly specific routes, at specific times, on a regular basis -daily, weekly etc. They will fly whether the plane is full or if there are only a few people on board.
When the term 'scheduled flights' is used it is generally used to describe traditional airlines that have been established for a long time such as BA or Air France or American Airlines. These airlines will fly both short-haul and long-haul routes usually between major cities.
The term flag-carrier is a legacy of the time when many airlines were in state-ownership and there were fewer airlines. The term is now effectively defunct but airlines such as BA still proudly fly the national flag and are referred to as 'flag-carriers'.
A charter flight is a flight that takes place as a result of a hiring agreement. Holiday companies will hire (charter) a plane and travel agents will sell tickets on the plane in conjunction with accommodation to people who want to go on a package holiday. Charter flights therefore usually fly to holiday destinations. Charter flights are often contrasted with scheduled flights but apart from the above they operate to regular, published schedules and there is very little difference.
Previously to get on a charter flight you would have had to have bought a package holiday -now companies are selling seats on the plane without the need to buy a package. This is great news for people who want to travel to destinations served by charter airlines but who don't want a package -for example people who have a holiday home at their destination or people who wish to make their own arrangements when they arrive.
Thomas Cook and Monarch are examples of charter flight operators that allow seats to be booked on their flights without a package.
No frills or budget airlines are airlines such as Ryanair, Easyjet, BMI baby and Jet2.
They fly short-haul routes that are a combination of the routes traditionally served by scheduled airlines: such as London-Paris, and the routes traditionally served by charter airlines: holiday routes such as London-Majorca.
Tickets do not have to be bought as part of a package.
The budget airlines are so-called as they try to keep their costs (and their prices) to a minimum. The service offered by these airlines is generally inferior to that of a normal scheduled airline. To keep the costs down, compromises are made: less prestigious airports are used, in-flight meals are available only at a cost, there are no complementary newspapers etc. The lower standard of service has allowed these airlines to be profitable whilst passing on the lower fares to customers.
As said at the beginning: there really isn't much difference between the types of flights anymore.
Scheduled airlines and no-frills airlines operate side-by-side on many routes and compete furiously for passengers. Scheduled airlines have reduced their prices to compete and so the differences between the two have become less pronounced.
The biggest change in recent years is the opening up of charter flights. They serve a whole host of destinations, (albeit mainly sunshine/ski holiday type destinations), and they now allow bookings to be made online for a seat on the plane at a reasonable fare.