Airline stocks topped gainers in the U.S. industrial sector ion Monday as analysts prepped for the industry's first earnings report due later this week from Delta Airlines (DAL) - Get Report.

Delta will report first-quarter results on Thursday. 

The gains follow news last week that the airline industry seems to be headed for positive passenger revenue per available seat mile. "Positive RASM has been achieved," J.P. Morgan analyst Jamie Baker wrote Wednesday, in a report issued after Delta reported better-than-expected December RASM.

Baker said RASM figures provided by Airlines for America showed flat international RASM and a 0.1% domestic RASM increase. Including regional carriers, consolidated RASM rose 0.2%, "the first instance of positive RASM in 23 months," Baker said.

Delta shares gained 0.9% in early trade but closed the day higher by a 9.2%.

American Airlines(AAL) - Get Report  , Southwest(LUV) - Get Report  and Alaska Air  (ALK) - Get Report were the top gainers, adding 1.8%, 0.7% and 0.6% respectively.