Consider the following financial data for American Airlines Group Inc. and Delta Air Lines, Inc. for the fiscal year 2023:

($ millions)	American Airlines Group Inc.	Delta Air Lines, Inc.
Net sales	$45,768	$49,634
Cost of sales	32,499	34,674
Gross profit	13,269	14,960
Operating expenses:
Selling, general, and administrative	6,734	7,312
Research and development	1,453	1,672
Operating income	5,082	5,976
Interest and other (income) expense	1,712	1,764
Interest and investment income	(538)	(584)
Earnings before provision for income taxes	3,908	4,796
Provision for income taxes	782	960
Net earnings	$3,126	$3,836

Required: a. Calculate the return on equity (ROE), return on assets (ROA), and return on financial leverage (ROFL) for American Airlines Group Inc. and Delta Air Lines, Inc. Assume a tax rate of 25%. b. Disaggregate the ROA into profit margin (PM) and asset turnover (AT) for both companies. Discuss the key factors affecting their ROA. c. Analyze the trend in operating income over the past five years. How does it impact their financial health and ability to invest in fleet expansion? d. Evaluate the debt-to-equity ratio for American Airlines Group Inc. and Delta Air Lines, Inc. What does it imply about their financial risk and leverage? e. Compare the operating profit margins of American Airlines Group Inc. and Delta Air Lines, Inc. What insights can be drawn about their cost control and profitability?