U.S. stock futures are down on Monday, drawing attention to specific stocks today. Caledonia Mining Corp. PLC (NYSE: CMCL) is expected to reveal quarterly earnings of 59 cents per share on revenue of $71.90 million. In after-hours trading, Caledonia Mining's shares dropped by 6% to $20.16. United Airlines Holdings Inc. (NASDAQ: UAL) plans to decrease scheduled capacity by approximately 5% in the second and third quarters, focusing on less profitable routes. For more details, visit Benzinga.com.