Even with the airlines losing zillions, they're still publishing some ridiculously cheap fares. Our fare of the day, for example, on June 22 is Dayton to San Francisco for $212 RT including tax. But like many cheap fares, this one is essentially sold out for most of the summer. The really cheap fares are only available on most airlines, domestically, from after Labor Day through October. And Tuesday and Wednesday, as always, are the cheapest days of the week to travel (that's because most business travelers begin their trips on Monday and return Thursday or Friday, and most leisure travelers leave on Friday and return Sunday or Monday).
That said, we've seen a number of super deals on US Airways for scattered dates in July and August. But you must use a flexible date search to find them.
Southwest has been playing around with unadvertised sale fares, too, especially for Tue/Wed travel in October. Try their "Shortcut" flexible date feature to find deals.