Americans probably haven't noticed much of a change in airline ticket prices since oil began to plummet. They shouldn't hold their breath.

That's because airline investors are more likely to be the main beneficiaries for quite some time. With benchmark West Texas Intermediate crude at a five-year low near $55 a barrel, many airlines have seen their costs begin to fall significantly in the last few months. Fuel accounts for a hefty 35 percent or more of operating expenses, according to industry analysts, meaning the savings can add up fast.