This week, four aerospace and defense stocks are improving their overall rating on Portfolio Grader. Each of these rates an “A” (“strong buy”) or “B” overall (“buy”).

Hexcel Corporation (HXL) is making progress this week as its rating of C (“hold”) from last week increases to a B (“buy”) rating this week. Hexcel Corporation develops, manufactures, and markets reinforcement products, composite materials, and engineered products. Shares of HXL have increased 7.2% over the past month, better than the 1.7% decrease the S&P 500 has seen over the same period of time. For more information, get Portfolio Grader’s complete analysis of HXL stock.

Engility Holdings, Inc. (EGL) is progressing from last week’s rating of B (“buy”) as the company improves to an A (“strong buy”) this week. Engility Holdings provides government services in systems engineering, training, program management, and operational support to the U.S. government worldwide. For more information, get Portfolio Grader’s complete analysis of EGL stock.

This is a strong week for Orbital Sciences Corporation (ORB). The company’s rating climbs to B from the previous week’s C. Orbital Sciences manufactures small space systems for commercial, civil government, and military customers. For more information, get Portfolio Grader’s complete analysis of ORB stock.

The rating of TransDigm Group Incorporated (TDG) moves up this week, rising from a C to a B. TransDigm Group is a global designer, producer and supplier of highly engineered aircraft components for use on nearly all commercial and military aircraft in service today. For more information, get Portfolio Grader’s complete analysis of TDG stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.