NEW YORK ( TheStreet) -- I like the Priceline.com ( PCLN) commercial in which pitchman William Shatner and an "enforcer" convince the front-desk clerk that a hotel room is a perishable commodity, and accepting a lesser amount that covers costs is better than receiving nothing.An airline seat is also a perishable commodity. Unlike most things you can buy, its price gets more expensive the closer it gets to its perishing point. And that point is every time a flight crew closes an aircraft door, right? Well, that need not always be the case, especially on longer routes. I used a Delta ( DAL) reward ticket recently to fly business class from Paris to Atlanta. The plane was full in the back but about half of the business-class seats were empty. That scene, repeated many times around the world every day, underscores that not only is it hard for airlines to make a profit, but its reputation doesn't include exceeding customer expectations. J.D. Power and Associates' most recent airline survey of such, conducted last summer, found a decline for a third consecutive year. Alaska Airlines ( ALK) ranked highest among the traditional network carriers for the second straight year. JetBlue Airways ( JBLU) was No. 1 among low-cost carriers for four years running. There are a number of things that airline companies could consider to boost revenue and customer satisfaction. (Those two measurements mustn't be mutually exclusive, which seems to be a corner that airline carriers have painted themselves into based on terms and conditions that many customers view as takeaways.) Here's one example of what could be done, with the example of my flight on Delta from Paris using a reward ticket for business class. It's criminal to me that half of business class was empty, given that airlines are losing money and aren't known for exceeding customer expectations. On most flights, airlines sell food and on international flights, they sell duty-free items, so they have credit-card processing machines onboard. Why not let people buy an upgrade once they're on board? That could be a significant amount of incremental revenue with little cost.