Heico Corp (HEI), an aerospace and defense company, saw its shares plummet 6.81% in the trading session on Tuesday. The stock's plunge came after the company reported disappointing fiscal fourth-quarter results, citing slowing demand and economic headwinds.

The key reasons behind Heico's stock plunge are as follows:
1. Sales Miss: Heico reported Q4 sales of $1.01 billion, missing analysts' estimates of $1.03 billion by 1.79%. This sales miss raised concerns among investors about the company's growth prospects and its ability to navigate the challenging economic environment.
2. Slowing Demand: According to the earnings release, Heico's sales growth was weighed down by supply chain challenges and slowing demand, particularly in the aerospace sector. This has fueled worries about the company's future performance and revenue growth potential.
3. Economic Headwinds: The company faced economic headwinds during the quarter, which impacted its sales and profitability. Analysts expressed concerns about the potential impact of these headwinds on Heico's growth prospects, especially in the aerospace industry.

Despite the disappointing sales figures, Heico reported earnings per share of $0.99, narrowly beating analysts' expectations of $0.98. However, this was overshadowed by the concerns over slowing demand and the challenging economic environment, leading to the significant stock price decline.