IT’S NOT EVERY DAY you see famous, brand-name American companies acting like 10-year-old girls. But that’s exactly how US Airways and the Internet travel site Expedia.com are behaving in their squabble over electronic booking fees. Consider:

A few days after Thanksgiving, a sharp-eyed, well-fed US Airways employee, conducting a “routine” internal audit, discovered that Expedia.com had “arbitrarily” and “unfairly” increased the amount it charges to book a seat on a US Air flight. Time was, you understand, that Expedia only charged its customers $5 to buy a US Air ticket. But those days, it turns out, ended sometime in November, and Expedia had raised the charge to a whopping $8.99 per ticket. The service fee for all other airlines–Expedia’s online travel database features over 400 these days–remained at $5. So you can see why US Air was peeved.