NEW YORK (TheStreet) -- Friday wraps up the busiest week in this earnings season with four more notable companies: Biogen  (BIIB - Get Report), AbbVie  (ABBV - Get Report), American Airlines Group  (AAL - Get Report) and Spirit Airlines  (SAVE - Get Report) are all due to report quarterly results before the opening bell.

American Airlines is expected by Wall Street analysts to report a profit of $2.60 a share on sales of $10.86 billion for its latest quarter, according to data compiled by Thomson Reuters. Analysts are forecasting a yearly increase in profit, but a year-over-year decline in revenue. In the same quarter of last year, the carrier earned $1.98 a share on revenue of $11.36 billion.

Earlier this month, American lowered its 2015 capacity growth guidance to 1%, down from its earlier forecast of 2%. The company is expecting full-year domestic capacity to increase by 1% to 2%, while international capacity is forecast to rise about 1%. Additionally, American said it expects second-quarter PRASM, or passenger revenue per available seat mile, to decline by 6% to 8%.

TheStreet's Jim Cramer, portfolio manager of the Action Alerts PLUS Charitable Trust Portfolio, said he's watching the airline group, which is "on fire." With good reports out of both Delta Air Lines  (DAL - Get Report) and Southwest Airlines  (LUV - Get Report), Cramer thinks Friday's earnings from American and Spirit will help "tell the tale" for the industry.

American Airlines provides scheduled jet services to about 160 destinations throughout North America, the Caribbean, Latin America, Europe and Asia. The company is based in Fort Worth, Texas.

On the economic calendar, we note key data including the flash reading of the Purchasing Managers Index (PMI) flash manufacturing index and new home sales.