NEW YORK (TheStreet) -- Investors should consider these seven stocks in the aerospace sector as "buy and trade" candidates in 2013. Each of them is rated either a strong buy or a buy.Like my post published Tuesday, 7 Conglomerates to Trade in Earnings Season, if you are already long these stocks, you should consider shifting from a "buy and hold" investment strategy to a "buy and trade" strategy. With aerospace stocks you have the volatility in reacting to Q4 earnings and you have the risk of sequestration spending cuts that will be negotiated later in the quarter. In a "buy and trade" strategy you take advantage of ups and downs in the price of a stock using GTC Limit Orders to buy weakness to a value level, and to sell strength to a risky level. With aerospace stocks, look for volatility vs. quarterly earnings and sequestration decisions in Washington. The aerospace sector is 3.9% overvalued and there are 11 of 16 sectors that are more overvalued. The seven companies I am profiling today report their earnings between Jan. 23 and Feb. 8, and I will be on the alert for upgrades and downgrades between now and then. Here, I show the current EPS estimates from Wall Street and will compare these numbers to more current estimates during the weeks these companies report. Three of the seven stocks are rated a strong buy according to www.ValuEngine.com and the other four are buy rated. Only two are undervalued but by just 4.4% and 0.7%. The other five are overvalued by 1.9% to 8.8%. One stock is down 5.8% over the last twelve months, and one is up just 2.6%. The other five have gained between 8.0% and 24.5% over the last twelve months. Gains over the next twelve months are projected to be between 7.0% and 14.5%. The twelve month trailing P/E ratios are favorable to reasonable between 9.4 and 15.8. All are above their 200-day simple moving averages so reversion to the mean is an issue in 2013.