Gone are the days when flying across the Atlantic would routinely cost a small fortune.

In fact, options for taking affordable transatlantic flights from cities across Western Europe have grown hugely with the arrival of new low-cost airlines and the introduction of stripped down fares from the traditional airlines.

Thanks to the amount of competition in the airline industry over this new battle ground, there are travel opportunities for those living all over Europe, and on the other side of the Atlantic, to take advantage of great fares.

Where can you fly?

One of the biggest success stories is Norwegian, which began as a small regional airline in Scandinavia, but now flies modern Dreamliner aircraft from bases in Barcelona, Copenhagen, London Gatwick, Paris, Rome and Stockholm to some of the main tourist and business destinations in the United States.

These include Los Angeles, San Francisco, Seattle, Chicago, New York, Denver and various gateways in Florida.

Some routes utilize the new Boeing 737 MAX aircraft on the relatively short hops from Belfast, Cork, Dublin and Edinburgh to cities such as Providence, Newburgh and Hartford -- all airports close to big cities such Boston and New York. Next year Norwegian will introduce a link between Dublin and Hamilton, near Toronto.

Another Nordic newcomer this year is Primera Air, which started out serving vacation destinations and is now using state-of-the-art Airbus A321neo planes on new routes from London Stansted and Paris to Boston, New York, Toronto and Washington D.C.

A more circuitous route across the Atlantic is via Iceland.

What was long a necessary stop for older-generation planes without the legs to cross the ocean nonstop is now used by airline WOW air and its sleek, purple planes to offer greater choice and rock-bottom fares.

With a whole range of starting points across Europe, passengers can disembark in Reykjavik and transfer to another aircraft with just as many options across America and Canada.

What's the catch?

So, how come it's suddenly cheaper to fly longer distances?

The common factor is that these are low-cost airlines who strip back their on-board offering to attract passengers with a basic "no frills" ticket price that's extremely attractive when compared to the standard prices charged by mainline carriers like British Airways, KLM and Lufthansa.

They also use the latest generation of aircraft which are much lighter and more fuel efficient, meaning its cheaper than ever to transport passengers over greater distances.

WOW air's CEO Skúli Mogensen says he sees his airline as a "logistics provider," much like Amazon, sending its goods from A to B and looking for ways to automate and reduce costs which will become "irresistible" to passengers.

Disrupting the market

The basic principle of cheap flights across the Atlantic has existed since the 1980s, when Freddie Laker started his Skytrain service between London and New York.

It was emulated by Richard Branson when he founded Virgin Atlantic in 1984. However, Laker was soon squeezed out, and Virgin later became a full service airline.

The difference today is that the traditional carriers are being forced to take notice as the young startups are seriously disrupting the market with flashy fares and marketing campaigns.

International Airlines Group (IAG,) which operates both British Airways and Spain's Iberia, recently founded its own low-cost offshoot called LEVEL. It targets passengers in Barcelona and Paris, offering similar basic fares and service to Norwegian.

Elsewhere in Europe, Germany's Lufthansa has developed a long-haul arm of its low-cost Eurowings subsidiary, whilst Thomas Cook has started a number of routes to US cities like Los Angeles, New York and Seattle from its bases in Germany and the UK.

Hand baggage only

Another way the big names are trying to attract back passengers is through a new phenomenon known as the "hand baggage only" fare.

If you try to book a flight with British Airways, Brussels Airlines or Virgin Atlantic you will be presented with this option, with a cheaper ticket price in return for no checked baggage and a few other restrictions.

The benefit here is that the frequent flier fans among you can still earn credits for your flights, which is rarely an option with the true low-cost airlines.

When taking advantage of a great price with Norwegian, WOW air, LEVEL or Primera, be aware that on-board service will be limited unless you pay for add-ons.

With the cheapest fares you won't be able to check in baggage, and there will be no free food or entertainment provided. But do you really need them?

A flight from Ireland to the East Coast, for example, rarely takes more than six hours, which isn't that difficult to endure without a meal or seat-back entertainment. Or you could bring an iPad and buy some snacks in the terminal before boarding.

In some cases, flying into smaller airports may mean extra travel time to your final destination.

For New York you may land at Newburgh Stewart in Orange County, for San Francisco you might end up across the Bay in Oakland. Hamilton, mentioned earlier, is around an hour south of Toronto.

Another tip is to book as early as you can. Look out for special offers and be flexible with your travel dates as airlines usually adjust prices based on demand.

The future?

These offers naturally benefit passengers in both directions, and thousands of Canadian and US citizens are now gaining from cheap fares when traveling to Europe.

Expect the likes of JetBlue and Southwest Airlines -- two of America's largest low-cost carriers -- to start looking into transatlantic flights in the future, whilst Canada's WestJet is already offering cheap tickets from its principal airports to Europe.

To date, pan-European airline group easyJet and Irish low-cost airline Ryanair have held back from announcing any transatlantic ambitions of their own.

As competition rises we're likely to see a fares war on key routes, particularly where the traditional airlines feel threatened.

But in the short term there may be some excellent prices to snap up.