As fossil fuel prices continue their upward climb, alternative fuel sources, once considered too expensive to even contemplate, are blazing new trails. Contrails, that is.

Several airlines around the world have boasted about their successful tests of alternative fuel sources. Using some form of plant based mixture, these airlines have determined the fuels to be identical to jet kerosene and environmentally superior. With all the talk about reducing greenhouse gases or paying penalties for polluting, the motivation seems clear – alternative fuels will be powering aircraft in the future. The question is how much of it.

Though the costs of biofuels are still prohibitively high for regular use, many airlines are moving forward with tests, realizing that production costs will eventually come down as biofuels become more common. According to scientists, biofuels derived from plants or food byproducts such as used cooking oil, meet the same jet fuel standards as traditional fuels. Jet engines should find the mixtures indistinguishable from the widely used Jet A fuel, and that is very appealing to airlines and aircraft manufacturers.

Confidence in biofuels is growing and each test that is passed brings the industry one step closer to widespread adaptation of the fuels. Whereas early tests of biofuels on commercial jets involved empty aircraft on test flights, several airlines have actually conducted scheduled commercial flights involving a mixture of traditional fuel and biofuels. In the U.S., Alaska Airlines has announced that 75 of its flights during November 2011 would fly with a mixture that includes at least 20 percent biofuels. The airline not only wants to prove the viability of the alternative fuel, but it also wants to show that its utilization should come sooner than later.

Once the production and refining of biofuels become more commonplace, their costs should go down. As airlines contemplate the rising costs of traditional jet fuel paired with the increased pressure from governments to reduce carbon emissions, alternative fuels become more appealing. This is especially true given that biofuel sources are varied, predictable and are expected to be a far less volatile alternative to the traditional fossil fuel sources. However, at nearly six times the cost of traditional fuels, biofuels still have some ground to cover no matter how appealing price stability sounds right now.