Delta Air Lines (NYSE: DAL) shares dove around 4.4% on Thursday morning following company guidance announcements that fell mostly in line with what the carrier had led investors to expect. The airline reaffirmed its full-year earnings guidance and tightened Q3 revenue to an increase of about 2-4%, narrowly improving on consensus estimates. As a result, the rapid Delta sell-off this morning caught many investors by surprise. Other airline shares broadly rose by between 0.5% and 1.5%, with some outliers like Frontier Airlines pushing gains of more than 5%.