The bigger they are, the harder they fall. Whoever came up with that phrase surely wasn't talking about the cost of flying. News comes this week that fuel surcharges for flights between Europe and the U.S. have hit record highs, and there is no sign of a drop in fees anytime soon.

Fuel surcharges have risen to up to US$420 on average for a round-trip ticket between the U.S. and Europe – even higher than the surcharges implemented during the last oil price spike nearly three years ago. The latest surcharges come on the heels of disappointing quarterly earnings for some U.S. carriers.

If you thought the cross-Atlantic fuel surcharges are high, consider that fuel surcharges between the U.S. and some countries in South America approach $600 for a roundtrip ticket and flights between the U.S. and Sydney can hit you with an additional $500. In 2008, the surcharges were $390 and $220, respectively.

The surcharges are global. Malaysia's Air Asia will have brought back fuel surcharges on its flights as of early May. The carrier had done away with them in November of 2008. Singapore Airlines, Qatar Airways, Japan Airlines, British Airways (and you can count on many more airlines) all will have increased fuel surcharges by the beginning of the summer travel season. Though it will be winter for Qantas' and Air New Zealand's home bases, the result will be the same for everyone: higher ticket prices.

Why won't airlines simply increase their base fares to avoid customers getting "surprised" when the fare they thought was a bargain gets tallied up to include all the extras? The answer is easy. Literally, it's easier for the airlines to tack on surcharges and fees for which they don't have to pay government and other taxes. The airlines also don't have to file their fees through a clearing house the way they do their air fares. Additionally, they don't have to include these fees in the commissions they pay to travel agents either. That is unless there's uproar, such as a recent class-action suit in Australia that swayed Qantas into paying commissions on such fees.

It's hard to say how long the surcharges will last or how high they will go, but if passengers start staying home because the cost of flying gets too high, maybe then we'll know the public's level of tolerance. If airlines are still losing money due to fuel costs at that point, they'll probably cut capacity instead of raising the surcharges even higher. But nothing is certain in this industry. Expect fewer and even more crowded flights if fuel prices continue to soar. In other words, don't get too comfortable.