CHARLOTTE ( TheStreet) -- The airline industry is set to start reporting unimpressive unit revenue growth numbers and analysts continue to reduce earnings estimates. Delta ( DAL) will lead off the September traffic reporting on Tuesday: Barclays Capital analyst David Fintzen said he expects Delta will report that passenger revenue per available seat mile increased by 1% to 3%. That would be at the high end. Fintzen expects US Airways ( LCC) to report a gain of 1% to 2%. JP Morgan analyst Jamie Baker expects United ( UAL) to report PRASM between minus 2% and minus 4%, based on the disappointing guidance > United issued last week. Fintzen expects industry PRASM growth of about minus 1% and said September should mark the low point. "We expect September to mark the lows for RASM growth this year, with improving trends a function of easing comparisons and, we suspect, slightly improving sequential trends," Fintzen wrote, in a recent report. "Our expectations for a return towards mid-single digit RASM growth in 4Q assumes 1.5 ppts of underlying revenue acceleration, with the industry on pace for 4% RASM growth given current demand levels." For the third quarter, CRT Capital Group analyst Mike Derchin expects the industry to report overall third-quarter PRASM growth of 1.8%, compared with 6.3% in the same quarter a year earlier. He said the fourth quarter should bring industry growth of 3.4% "against more normal comparisons." "In hindsight, the excise tax holiday and Hurricane Irene last year was worth about 200 basis points in PRASM growth," Derchin wrote. "Also, the timing of the July 4 holiday and Jewish holidays negatively impacted business travel this year." Derchin said the industry earnings outlook has diminished due to the rise in fuel prices and slowing unit revenue growth. "The main change we have decided to incorporate in our earnings models is to assume that continuing political uncertainty in the Middle East and weak dollar results in WTI crude oil trading toward the top end of the recent $85 to $100 per barrel range," Derchin wrote, in a recent report. "We now expect a net profit of $2.1 billion in 3Q12 compared with $1.8 billion for 3Q11 and our prior forecast of $3.5 billion." Derchin continued: "If jet fuel prices remain elevated, we expect airlines to adjust capacity downward again and push prices higher, particularly during peak travel times. We are forecasting that it won't be until 1Q13 that the current jet fuel spike is fully offset by carrier actions."