Shares of American Airlines (AAL) dropped in early trading after the company lowered its total revenue per available seat mile guidance for the second quarter.

UPDATED Q2 OUTLOOK: In a regulatory filing out this morning, American Airlines lowered its TRASM guidance for the quarter to up approximately 1%-3% year-over-year from its previous view of up about 1.5%-3.5%. This change from previous guidance is due to lower than anticipated domestic yields, it said. Additionally, American said it now expects Q2 cost per available seat mile, or CASM, excluding fuel and other items, will be up about 2.5% year-over-year, below its previous guidance of up about 3.5%. The carrier said the lowered guidance is due primarily to lower than anticipated maintenance expense and the application of higher airport rent settlement credits.

OTHER GUIDANCE: The company expects its total pre-tax net special items in Q2 will approximate $215M. The company also lowered its outlook for Q2 consolidated capacity to 72.9 billion available seat miles from 73.1 billion, while increasing its estimate for the average per-gallon fuel price to $2.24-$2.29 from $2.18-$2.23.

UPDATE ON PSA AIRLINES: Additionally, American provided an update on PSA Airlines, one of its wholly-owned regional carriers, which experienced an IT issue on June 14 that impacted its operations and resulted in the cancellation of approximately 3,000 flights over the following week. American said it estimates that the event impacted pre-tax income negatively by about $35M.

ELIMINATION OF PLASTIC STRAWS: Meanwhile, Reuters reported this morning that American Airlines will no longer offer plastic straws and stir sticks onboard its flights and in its lounges. Beginning this month, drinks in its airport lounges will come with biodegradable straws and wooden stir sticks instead of plastic utensils, while the phase-out onboard its planes will begin in November, with bamboo replacing plastic straws and stirrers. This follows an announcement by Starbucks (SBUX) this week that it will eliminate plastic straws, as well as similar plans by Sea World (SEAS), Hyatt Hotels (H) and Royal Caribbean (RCL).

PRICE ACTION: In early trading, American Airlines is down over 3.4% to $37.79.