The world's three largest airlines all saw the same thing in the first quarter: financial losses and stabilization in passenger traffic. "Things aren't good, but they also aren't getting any worse," said Ed Bastian, president of Delta ( DAL), on a first-quarter earnings call Tuesday. "The pace of decline in business yields and bookings has definitely slowed. "While we've seen signs of stabilization, we're not ready to call a bottom yet," he added. Bastian echoed what American ( AMR) and Southwest ( LUV) said last week. In terms of passengers, Southwest is the largest carrier, followed by Delta and American. All three said traffic seems to have stabilized, but yields from ticket sales declined from a year earlier. Fares are lower partially because fuel costs have receded and partially because business travelers are flying less. At Delta, passenger revenue per available seat mile fell 12% during the first quarter. For May and June, domestic booked load factors are down about two to four points from March and April, Bastian said, while international bookings are down four to six points. "We are expecting demand to build closer in," he said. Last week, Southwest CEO Gary Kelly said that. "In February, traffic continued to get worse on a weekly basis (but) we have not seen that decline continuing throughout March and then now into April." American also said it was seeing stabilization in bookings: CFO Tom Horton said the carrier's first-quarter loss was less than what it expected a month ago, thanks to "close-in traffic build," which boosted revenue. "It's too early to tell whether that portends a positive trend," he said.