Since the popularity of charter jets is increasing, the offering of one-way flights is becoming more popular as well. Charter jet companies will often quote a customer the price of chartering a jet for a one-way flight due to the ability of that company to charter the jet back to its origin with a new customer. This also allows the client to travel between airports or cities while taking breaks to relax. If a company's CEO needs to travel to different parts of the country, he may want to spend a week in each location. One-way trips allow him to do so at an affordable price. Otherwise, the cost of parking a charter jet at the airport for the time it would take that CEO to complete his business and move on could, in some cases, be more than the actual price of chartering the jet.
When talking about a more commercialized aviation industry (relating to the airlines), one-way flights can cost the client more than what is affordable. An airline has more invested in flying from one place to another. It can cost more fuel to climb, taxi, and descend than during the entire cruise portion of the flight. Airlines don’t sell seats on their gigantic turbojets to make a profit, they sell seats to cover their costs. A client wanting only a one-way ticket does not guarantee the airline a return passage, so the airline is reluctant to sell the ticket for a cheaper price. They want a customer who is going to fly their airline more than once. So, typically, a one-way ticket will cost almost as much, if not more, than a round-trip ticket.
Another common meaning for one-way in aviation is the direction of flight. In the aviation world, there are airways defined by magnetic or satellite-plotted courses in which aircraft fly. Certain airways are designated as one-direction flight airways, much like a one-way street. These airways can be one-way flights all the time, or they can be designated as such only during certain hours of the day. One-way airways can be two-way traffic but with one-way traffic designated to a particular side of the airway, just like a two-way street.